Spec Sheets for the new Danley Monsters are online...be afraid, be very afraid! [Text View]

Soundood

05-27-09, 04:25 PM

Remember also, that even if you put a filter on, that sub will still have response down below 16 hz since the response rolls off ...it doesn't stop cold. Also keep in mind that the spaces that sub is designed to fill (you know, 1000 seat theaters, concert halls, stadiums) will require the roll off to avoid over excursion. I'd be willing to bet that in a tiny little home theater (you know, 20,000 cu. ft) you may not need as much roll off down below because the excursion and output capabilities on that sub are so monstrous it will never even remotely approach its' limits.

If you look at the infamous Quad TH-50 Imax setup, it still has massive amounts of output at 12 hz even though it is being filtered (my understanding is that setup had so much output down low, it exceeded the test instruments's capability to measure it). If you look at the frequency graph, which goes down to 10 hz. It still shows 80 db of output at 10 hz. Not very impressive? Keep in mind, Danley does a lot of their testing OUTSIDE (no room, no room gain) and that is WITH a steep roll off so they could get the most out of it. That is simply RIDICULOUS! Can you imagine what 4 of those things would do in that IMAX Theater? They'd need paramedics standing by! Point is, you may not need a steep roll off with it in a lower volume application as long as you remain within the insane capabilities of the beast.

Regarding amps, it isn't as bad as it seems. The lit says the following..."The impedance shall be nominal 2 ohm, 2 x 4 ohm or 8 ohm via internal jumper." The test was done at 2 ohms to maximize the output. But you don't need to run it at 2 ohms, meaning your amp setup is actually pretty flexible. You can set it to the 8 ohm setting and use an amp that can be bridged into 8 (something like a Face Audio F-2000TX will do 3.3 kilowatts into 8, a QSC RMX-5050 will do 3.2 Kilowatts, the Danley Labs DLSA-6.5 (yes, Danley has amps!) will do 4.4 KW into 8. You can also use some of the less dear sub amps out there and simply use two of them bridged into 4. A pair of Behringer EP-4000's will give you 2 Kilowatts/ch bridged into 4, a total of 4 kilowatts, and will run you less than $800. Sure you won't have quite as much output but "less" is relative! I'd be willing to bet that any of the above would probably suffice to cave in your ribs in a home theater.

What does it cost? Yes it is SUBstantial, but actually less or considerably less than some of the other super high end subs like the Krell MRS, the Wilson Thors Hammer, Velodyne DD1812, or JL Audio Gotham, none of which are even in the same universe as this for output and none are likely better for sound quality (after all, it IS a Danley product and if there is one thing Danley subs are known for it is sound quality.) If you need pricing, PM me.

otk

05-27-09, 04:53 PM

I was under the impression that you had sworn off subs that use high pass filters. The specs for this call for a 20 Hz HP filter @ 24db/Butterworth.

i did

that was just some tomfoolery

kinda rang funny to me to see "houses of worship" listed under "applications". i realize that it's probably meant for digital organs

but thanks for playing :)

spyboy

05-27-09, 05:09 PM

i did

that was just some tomfoolery

kinda rang funny to me to see "houses of worship" listed under "applications". i realize that it's probably meant for digital organs

but thanks for playing :)

What strikes me as funny is the "one of a kind high-end home theatre" application.

My sense is that other than "the bland", there are a only a few others of these big Danleys and JTRs in "high-end home theatres."

So yeah, one of a kind is about it.

Ricci

05-27-09, 05:27 PM

Hi Ricci,

The specs Danley provides are rather detailed, and if you look you will note that the measurement and sensitivity is a 2.8V sensitivity, as that's what many others rate their speakers at, regardless of load. Being a 2 Ohm load though, that is 4W of input, making for a better 1W/1m equivalent being about 94dB in that 17-18Hz range. That is still staggeringly impressive as it might be able to tickle 130dB @ 1m down that low with a BIG amp. An average sensitivity of 103dB @ 1W/1m from any device extending below 20Hz is quite the accomplishment. :eek:

Right you are sir...Shoulda noticed that. As you say even 94db 1m halfspace sensitivity is astounding at those kind of freq's.

Soundood,
Running it at an 8ohm load with a big amp seems better. For some stupid reason I wasn't thinking about running it at 8ohm nominal instead of 2. You could run a pair at 2ohms each off of one amp if you had the right one but it would take a hefty beast (cough PL9.0 cough cough...).

brandonnash

05-27-09, 07:48 PM

Enough with the drooling, because that is what I am doing. I need to be brought back to earth. My head is in the clouds thinking of 2 21" subs in a tapped horn. I'm inches away from robbing a bank to try to get one of these. Don't worry, I won't, but to bring me back from the stratosphere, what's the cost of one or both of these?

Oh, and I was thinking of an ultra sick application. A 221 for the low end (40-50 hz and below) and a 812 for midbass backed by a total of about 15000 watts. This setup=no house left standing and exactly 1 divorce.

2100

05-27-09, 09:52 PM

What strikes me as funny is the "one of a kind high-end home theatre" application.

My sense is that other than the "bland", there are a only a few of these big Danleys and JTRs in "high-end home theatres."

So yeah, one of kind is about it.

At that kind of price and size, it definitely is one of a kind...no hiding from that. :D It is after all more intended for commercial purposes.

Lets look at the graph, the freq response graph gradient starts to really dip at 22Hz (the knee, sorta). Look at a PB-13U from HTS sub test, the knee is at about 19Hz.

Even if I take it down to 20Hz for the TH-221 which is a little unfair, its about 94dB for 1m 1 watt (after factoring in Z=2ohms). Juice it 6kW program, it'll do about 131dB program....134dB peaks for 20Hz.

Take the PB-13U CEA max output peak fig from HTS, we'll take it as 109dB 2m at 20Hz (its listed as 108.5), or 115dB 1m. 4 gets you to 127dB, 8 units get you 133dB. That's assuming *perfect coupling* between the huge number of subs.
8 x SVS is more expensive even with a good 10-15% disc. But add in a very good amp it will be quite a fair bit more expensive then of course, 2nd hand contains the cost if one does not mind that.

From 25Hz to 50Hz its approx the same for both. The TH-221 pulls away from 60Hz to whatever freq you wanna take it up to, its a narrow band but that is still in the punch territory. We are talking in the region of 16-32 SVS for the same freq (again assuming perfect coupling)...there is enough kick to get the lung cavity have that "itchy and you wanna cough" and dizzy vision feel in a regular room.

If your application usually hovers at max SPL as headroom for the peaks, it makes sense to set the protection at 20Hz. You can set it as a matter of personal preference at 14Hz, 16Hz and even use EQ no issue, but the B&C drivers are expensive at over usd700 ea. For SR use, I'd guess you may have more occassions that need you to flirt close to the limits more often and for a longer period, as compared to HT demo use ie. more likelyhood % for damage.

Actually measurements and figures are one thing, listening in real life is another. I actually experienced 7 SVS + 1 nearfield M&K 5K in a small 1k cu ft room and sheesh its power. But if you are talking about bass , my TH-112 is not missing a heck lot even though it stops at 30Hz, its noticeable definitely but it is not like absolutely day-and-night the 30Hz tapped horn sounds like HTIB kind. But anyway i'll be adding something soon for the lows dah.... haha. :D

Mike Hedden

05-27-09, 11:49 PM

As impressive as they are, they are not designed to play below 20hz and they call for a sharp filter below that point.

Amazing the confidence of your post, would you care to elaborate on why the TH221 can't play below 20Hz? Just for the record, I demo this sub every day in our demo room we typically don't use a high pass filter. We do recommended high pass filter for all our subs used in commercial applications, i.e., rooms typically bigger than most homes, seating several hundred if not multiple thousands indoors or outdoors.

Mike Hedden
Danley Sound Labs, Inc.

mojomike

05-28-09, 12:14 AM

Amazing the confidence of your post, would you care to elaborate on why the TH221 can't play below 20Hz? Just for the record, I demo this sub every day in our demo room we typically don't use a high pass filter. We do recommended high pass filter for all our subs used in commercial applications, i.e., rooms typically bigger than most homes, seating several hundred if not multiple thousands indoors or outdoors.

Mike Hedden
Danley Sound Labs, Inc.

Mike, I didn't say the TH221 can't play below 20hz. I read the pdf Spec sheet on the sub.
http://www.danleysoundlabs.com/pdf/th%20221%20spec%20sheet.pdf

It give specs:
Operating Frequency Range
22-180hz -3db
18.5-200hz -10db

Recommended Processing ................ 20 Hz HP @ 24 dB/Butterworth

What I said was "they are not designed to play below 20hz". To me, the above specs certainly would lead one to believe that <20hz performance is not their forte.

If they are designed to play below 20hz, I'd suggest modifying the spec sheet because it gives the wrong idea. If you don't typically use a high pass filter, why don't you say that instead of calling the 20hz HP "Recommended Processing"?

2100

05-28-09, 08:42 AM

Well you'd certainly need at least 2 TH-221 or 1 TH-812 for this room. :D

http://www.tfwm.com/cnn-0409danley

Mike Hedden

05-28-09, 10:03 AM

Mike, I didn't say the TH221 can't play below 20hz. I read the pdf Spec sheet on the sub.
http://www.danleysoundlabs.com/pdf/th%20221%20spec%20sheet.pdf

It give specs:
Operating Frequency Range
22-180hz -3db
18.5-200hz -10db

Recommended Processing ................ 20 Hz HP @ 24 dB/Butterworth

What I said was "they are not designed to play below 20hz". To me, the above specs certainly would lead one to believe that <20hz performance is not their forte.

If they are designed to play below 20hz, I'd suggest modifying the spec sheet because it gives the wrong idea. If you don't typically use a high pass filter, why don't you say that instead of calling the 20hz HP "Recommended Processing"?

As I said in my previous post, the vast majority of our work is in large commercial applications wherein the recommended high pass is essential.
Danley is and always will be honest perhaps to a fault in our specifications hence we measure our subs outdoors and ignore room gain. But numbers only tell a portion of the story. I know room gain is real in small room acoustics but also don't think you can take our outdoor measurements and compare them to ones that are totally dominated by room gain and try to make a comparison. Illka's measurements on another fourm clearly show that in many cases the measured response at say 80dB versus the maximum output is anything but linear. Many products he measured won't give you 20dB of dynamic range and even at that it is typically heavily tilted to the upper end of the sub, i.e., 50Hz+.
Put another way, anyone that attended Brandon's GTG would probably agree that the published specs didn't prepare folks for how stunningly well the TH50 performs. Or even another way...what other manufacturer can you name that using only four of their subs can flood a commercial Imax/Omnimax theater with reference quality and quantity of bass? Or using on six of their subs can flood a 7200 seat auditorium?

Mike Hedden
Danley Sound Labs, Inc.

mojomike

05-28-09, 10:12 AM

I don't at all doubt what you're saying, but prior to you saying it, all I had to go by was a spec sheet that recommended a 24db/octave 20hz HP and -3db point at 22hz.

brandonnash

05-28-09, 11:46 AM

If I had one of these subs I would almost certainly have a filter on it. I do listen loud at times and anyone with a fast car will tell you they drive faster at times because they have it. If I had this beast of a subwoofer I would play it loud. I would be concerned for the drivers trying to play the lightning strikes from wotw at 125 or 130 db so I would use a filter. I don't know about a 24 db butterworth at 20 hz, maybe something a little lower with not such a steep slope.

Mike Hedden

05-28-09, 12:00 PM

I don't at all doubt what you're saying, but prior to you saying it, all I had to go by was a spec sheet that recommended a 24db/octave 20hz HP and -3db point at 22hz.

No problem. Thanks for the input and taking the time to post, it is essential in us becoming better as a company.

Mike Hedden
Danley Sound Labs, Inc.

mojomike

05-28-09, 12:12 PM

Thanks, Mike. I'd certainly love to have an opportunity to hear one of the beasts some day.

Ricci

05-28-09, 12:32 PM

I think what Mike H. is saying is that comparing a sub that claims 10hz output but only has maybe a clean 90db in room at 10hz and 110db at 20hz to something that will do likely >135db at 20hz in room but claims 18hz extension is a little silly. Even though the effective knee might be 20-22hz it has so much headroom that it can useably extend lower than you would think.

I was at the GTG and the TH50 was mean. Like pants flapping stuff falling of the walls mean. Also clean while doing it. Adding another clean 10 or 12db on top of that...We had some loud subs (for HT) there too and stuff that I felt was a wee bit better at presenting the <20hz movie content, but the TH50 easily won the visceral impact and massive headroom award by a mile...

MKtheater

05-28-09, 03:52 PM

I have experience with folded horns in my 2300 cubic foot room that rolloff at 40 hz. You guys have to remember what these are designed for, huge rooms that are bigger than commercial theaters. In a regular HT room these become a different animal. No filters will be needed, trust me, HT peaks would be no problems. To give you an idea, my dual 18 inch folded horns with just 1000 watts per channel into each would reach 130 db's easily with movies like WOTW. They were flat all the way down to 15 hz in my room with room gain. I used to play that Pulse scene with them and it would shake the house no problem, no bad sounds, no bottoming, nothing. I never used any filters or EQ. These things in my room would go down below 10 hz in my room with alot of output, I bet at reference levels. The folded horns were awesome in my room and gave me more output down low than I would have ever imagined.

bossobass

05-28-09, 04:03 PM

...being about 94dB in that 17-18Hz range. That is still staggeringly impressive as it might be able to tickle 130dB @ 1m down that low with a BIG amp.

Any idea what the distortion levels would be at 130dB at 1M at 16Hz with a BIG amp?

Danley is and always will be honest perhaps to a fault in our specifications hence we measure our subs outdoors and ignore room gain. Illka's measurements on another fourm clearly show that in many cases the measured response at say 80dB versus the maximum output is anything but linear. Many products he measured won't give you 20dB of dynamic range and even at that it is typically heavily tilted to the upper end of the sub, i.e., 50Hz+.

Mike Hedden
Danley Sound Labs, Inc.

When looking at Ilkka's test results of the LMS-18/PR sub, make the adjustment to be an equivalent comparison.

The 221 uses 60 cubic feet of space. That's the equivalent to 8-LMS5400-18" + 2-PR systems at 200L each.

If we normalize to 1M, we get progressive sine wave sweep maximum numbers to 139dB, with 2dB of power compression and 5% THD, with THD limited burst peaks to 145dB.

That's with a much flatter response from 20-100Hz than the posted 221 response, not tilted toward 50Hz.

We also see the familiar skyrocketing THD numbers below tune, which most people seem to be OK with in quoting in-room or outdoor extension numbers, but it's the price one pays for an alignment that offers flat response to 20Hz with a steep roll off below that. Maybe the tapped horn is immune to this phenomenon?

This system would cost around $15,000.00, but, in relative terms, that's less than 2-JLA Gothams. Using John's new 18" drivers + PRs will probably be in the ballpark for 1/2 the price. We could double MKTheater's system to 16X18" for even less money, sensitivity being irrelevant.

As far as the TH-50 goes, at 24 cubes, 3 of the LMS PR subs, or MK's system, would easily compete in the same space.

What we don't have are the same test results for the 221 for comparison, so it seems to me that bringing up Ilk's results for comparison to honest measurements of the 221 requires showing those results.

Any power compression sweeps/THD numbers of the 221 to 139dB available?

I'm only curious, since the subject has been brought up, and is an interesting one at that.

Bosso

Tom Danley

05-28-09, 06:30 PM

Mike Hedden

05-28-09, 09:13 PM

The 221 uses 60 cubic feet of space. That's the equivalent to 8-LMS5400-18 + 2-PR systems at 200L each.

If we normalize to 1M, we get progressive sine wave sweep maximum numbers to 139dB, with 2dB of power compression and 5% THD, with THD limited burst peaks to 145dB.

That's with a much flatter response from 20-100Hz than the posted 221 response, not tilted toward 50Hz.

Many of Illka's measurements clearly show my point that there are many subs claiming sub 20Hz responses that cannot keep the same response at higher levels.
I also find it interesting that in your post you take our actual outdoor measurement and compare them to a compilation of subs and make an assertion that the compilation yeilds a better response.
This makes my point, one (ours) is real, the other is speculation. Put the actual system together, measure it the same way we do, and only then do you have the ability to make accurate comparisons.

Mike Hedden
Danley Sound Labs, Inc.

bossobass

05-29-09, 12:01 AM

Hi Bossobass, all

Bossobass asks some questions related to equivalency of Tapped horns vs other approaches.
Basically, so far, the Tapped horn has held an advantage over other designs I have tried over the years.
It has that advantage within a size range related to the low frequency corner however, you can’t just make a 20Hz horn the size of a shoebox like one could in theory with a vented or passive radiator system.
Otherwise per dollar, per cu foot, per low cutoff and output, once your large enough to make one work well, Tapped horns are generally unbeatable.

In addition, it is worth mentioning that the curves you see for the TH-221 and TH-812 were Voltage referenced, as Mark points out the impedance has to be compensated to get to nominal 1W1M efficiency. In the case of the TH-221, the Rmin is about 2 Ohms and then would be a ‘safe” rmin for a 3 Ohm nominal rating (like 6 Ohm’s on an 8 Ohm driver). In which case, a 1W 1M sensitivity would be 4.2dB lower than the curve or about 105.5 at 30Hz, if one said the 2Ohm min was the nominal load then it would be –6dB from the curve.
Also, this was measured at 10 meters in halfspace at 28.3Vrms so the actual SPL at one meter was +20Db over the measurement curve.

We do this at 10 meters because once the woofer system is large enough to take up a significant space, then that space is distorted compared to free propagation and what you measure up close doesn’t allow one to predict exactly how loud it will be at say 100 feet.
For acoustical design, you have to have the standard 1 meter number that reflects the far field fall off.

Bossobass, distortion is nearly always a function of driver motion, it gets worse faster than the fundamental SPL does with increasing level.
The increase you mention is a function of reaching the system corner, in a sealed box, the excursion reaches a maximum and SPL falls –12 dB/oct, in a vented box, the output falls about 24dB/oct and the excursion increases rapidly.
A Tapped horn is often in between reaching –18 –20dB per octave far down slope, excursion can increase or act like it is a sealed box depending on the driver and horn alignment. In the TH-812, the excursion below the low corner is much like a sealed system, the TH-221, somewhat less so.
Lastly, unlike the direct radiator, the Tapped horn has a casual acoustic low pass filter in it, usually it is a few hundred Hz (above crossover) depending on the geometry and this attenuates frequency components the driver inevitably produces above that (distortion).

So far as the response shape, wherever these go, they are EQ’d to get the desired “in room” response. The act of tilting down the upper response when needed with EQ simply gives you headroom where most of the transient spectrum is, it is the opposite of “lifting up” with EQ which costs you dynamic headroom.

Even one TH-221 sitting in the middle of a parking lot, will not have the same response as it would against a wall outdoors or let alone in a room.
Horns have a response which is much more dependant on the immediate physical surroundings of which there aren’t any (except for the ground haha) in half space. Additional things like a wall or corner, in addition to being a local fractional space can actually become part of the horn, in which case the sensitivity goes up and the low corner down.
In other words, the physical surroundings can be used to extend the corner and increase the sensitivity in use but that isn’t what you see measuring one in half space for a spec sheet.

On Power compression, you ask;
Any power compression sweeps/THD numbers of the 221 to 139dB available?

No, at least not now.
Measuring distortion at low frequencies should also be done outdoors but once your getting in the 120’s there is an issue with neighbors and many slow TEF sweeps.
Also, in commercial sound there isn’t any particular standard to compare to, heck, most subwoofer companies in commercial sound don’t even have a meaningful response curve.

Best,
Tom Danley

Thanks for the input, as always, Tom.

Yes, I agree, and it's a given for discussions sake that commercial concerns don't offer much in the way of objective specifications. That wasn't my point at all.

Bossobass asks some questions related to equivalency of Tapped horns vs other approaches.

No, actually, I was responding to Mike's comments, which give the impression that the test results that Ilkka has compiled show non-linear response from 20-80Hz and limited dynamic range.

My response was based on my opinion that this is an unfair comparison, given the size and scope of a 2x21" loaded tapped horn of 60 Ft^3 powered by 6KW.

In the equivalent space, multiples of the example I cited from Ilkka's list will offer comparable output and linearity of response while exhibiting very low non linear distortions.

The points I stressed are power compression and non linear distortion. This is an area that, although commercial concerns do not (and probably never will, since the tests tend to yield very unflattering results) post distortion test results, many of them have been tested independently by a half dozen credible people, and the results carry weight in the HT arena.

Since there are no such test results, I was interested in your input regarding the unique behavior of the TH-221 vs other alignments. You said:

A Tapped horn is often in between reaching –18 –20dB per octave far down slope, excursion can increase or act like it is a sealed box depending on the driver and horn alignment. In the TH-812, the excursion below the low corner is much like a sealed system, the TH-221, somewhat less so.

Is this a roundabout way of saying the TH-221 will exhibit more THD below the corner than a sealed alignment, even though it's rolling off faster? Does your answer also mean that a HP filter was used for the measurements of the TH-221 posted in the OP's link? I ask because the graph clearly shows a 4th order roll off.

I appreciate the answer regarding power compression, but you do list max and peak SPL numbers. So, what method do you use to arrive at those? Are they extrapolations?

BTW, I always appreciate your posts, and congrats on the CineMonster.

Bosso

bossobass

05-29-09, 12:02 AM

This makes my point, one (ours) is real, the other is speculation. Put the actual system together, measure it the same way we do, and only then do you have the ability to make accurate comparisons.

Mike Hedden
Danley Sound Labs, Inc.

On Power compression, you ask;
Any power compression sweeps/THD numbers of the 221 to 139dB available?

No, at least not now.
Measuring distortion at low frequencies should also be done outdoors but once your getting in the 120’s there is an issue with neighbors and many slow TEF sweeps.
Also, in commercial sound there isn’t any particular standard to compare to, heck, most subwoofer companies in commercial sound don’t even have a meaningful response curve.

Best,
Tom Danley

Bosso

Mike Hedden

05-29-09, 09:03 AM

No, actually, I was responding to Mike's comments, which give the impression that the test results that Ilkka has compiled show non-linear response from 20-80Hz and limited dynamic range.
Bosso[/QUOTE]

I just looked over five or six subs on Illka's post at home theater shack and everyone I looked at had similar non-linear responses at higher output levels. One example I've attached is the JL Fathom113. By my reading that is only 15dB of dynamic range before you start seeing a substantial response roll off. I'm not saying there aren't products that don't maintain linear response but so far all the one's I've looked at indicate they are in a tiny minority.

Mike Hedden
Danley Sound Labs, Inc.

2100

05-29-09, 09:13 AM

Well this just ran through my mind. 60 cubes is the number. However the real-world application for 8 x 18 plus 16 x 18 PRs means a lot of real-world volume. You get EIGHT 18-inch woofers firing forward plus SIXTEEN 18-inch PRs firing sideways.

It's double of robertcharles system. Say 2 columns of 4 active woofers each firing forwards and 8 PRs each firing sideways. You will need some space for the PRs to breath too, perhaps at least 10 inches each side, so that's more volume needed. Frontal would be 4 x 18-inch drivers tall (say 88 inches tall for the cab) and maybe 40 inches total width needed for the PRs to breathe, for each column. There are 2 columns.

The TH-221 is 28" x 60" frontal, but it would be deep at 60". There is only "one column".

You'll also need more amps and spend more amp dollars for the PRed DIY solution. Each driver can take 3kW program? But of course DIY can always be cheaper depending on how you do it. I do a mixture of DIY and commercial in my system, both have its pros and cons. In my country, the same amps cost about 30% more than in USA, eg QSC, Camco. Also DSL has really good shipping rates.

craigsub

05-29-09, 11:54 AM

Bosso - You mention "John's new drivers and PR's" ... do you have a link with specs and pricing available on it ?

Tom Danley

05-29-09, 12:09 PM

Hi Bossobass
You had written;
“In the equivalent space, multiples of the example I cited from Ilkka's list will offer comparable output and linearity of response while exhibiting very low non linear distortions.

The points I stressed are power compression and non linear distortion. This is an area that, although commercial concerns do not (and probably never will, since the tests tend to yield very unflattering results) post distortion test results, many of them have been tested independently by a half dozen credible people, and the results carry weight in the HT arena.

Since there are no such test results, I was interested in your input regarding the unique behavior of the TH-221 vs other alignments. You said:
Quote:
A Tapped horn is often in between reaching –18 –20dB per octave far down slope, excursion can increase or act like it is a sealed box depending on the driver and horn alignment. In the TH-812, the excursion below the low corner is much like a sealed system, the TH-221, somewhat less so.
Is this a roundabout way of saying the TH-221 will exhibit more THD below the corner than a sealed alignment, even though it's rolling off faster? Does your answer also mean that a HP filter was used for the measurements of the TH-221 posted in the OP's link? I ask because the graph clearly shows a 4th order roll off.

I appreciate the answer regarding power compression, but you do list max and peak SPL numbers. So, what method do you use to arrive at those? Are they extrapolations?”

Hi Bossobass

First of all, you will have to assume that our market is not the home market although I am pleased that some are finding our products to be usable in the home.

We supply more technical data about our products we sell than most of the companies involved, how many companies in the home market have an independent lab take their data?
How many supply polar information let alone full spherical data like the CLF files we offer, don’t they think, “where the sound goes” is important?
How many even have a usable response / sensitivity curve done in a universal and repeatable way?
The bottom line is we already supply more technical data than most in our market, if you don’t believe it, go look..

Now, you refer to Illka, I have seen his testing procedure and it is logical for what he’s trying to get to (maximum sustainable level limited by THD or amp limiting).
Also, from what I understand he decided to do this on his own so I am not sure how his level of information compares to what hifi subwoofers come with as in spec sheet.
I don’t know if he is still doing these tests but maybe it would be fun to send a box or two to him to measure that way. It will be interesting to see if he can get the cops and neighbors to offer their opinions..

So far as excursion, the point is that all systems have a sharp increase in distortion when they exceed the linear portion of the motor’s operation. What you speak of is both level, frequency and alignment dependent.

You have a real concern about power compression;

I am familiar with this subject and have worked on it in the past.
http://www.aes.org/e-lib/browse.cfm?elib=5023

The issue is, the effects of VC heating begin to show up as a measurable change in performance beginning somewhere between 1/10 and 1/8 rated power typically.
This does effect all drivers, ours too, but it does not effect all systems equally, an efficient horn will suffer less as it’s average impedance is raised by the acoustic loading.
For instance in a horn which was 50% efficient, half of the electrical power is dissipated as I^2*Rdc in series with an equal acoustic resistance.
In that efficient range, the impedance is twice that of the Rdc and now changes in Rdc have a smaller effect on alignment and response change.
I don’t know if that helps or if the driver data helps, we use a variant of this driver, which has shown to be pretty stout;

http://www.bcspeakers.com/product.php?id=0000000160

Model a pair of these in a box of your choice, compare the difference between the TH-221 response curve and the prediction and you see the acoustic gain the Tapped horn imparts (subtract about 4.5 dB from the curve and spec for 1W1M style figure)

As you can see from the driver’s thermal rating, we could have elected to have a higher power rating.
For example, 2000Watts AES pink noise rating for each driver requires an 8000 Watt amplifier as the peak to average ratio is 6dB.
This is much more of a thermal test than one which represents program as even compressed FM radio dance music has around 10dB peak to average level.

Bottom line, even with the drivers exposed to outside air, unless your adding active cooling, your more or less stuck with the driver motor’s thermal properties like how much surface area the coil has to dissipate heat, is it a large coil with a slow thermal time constant or a small coil with a faster time constant.
In any case our products are not immune to this or any of the other short comings real loudspeakers have.
On the other hand, once your talking about studly drivers, what subwoofers are called on to do is less thermal and more dynamic, you more likely to bottom out a subwoofer or make it complain audibly than smoke a voice coil.

What the home theater focus seems to miss I think is that much of what we listen to is not a sustained signal but has large changes in level which also represent low frequency content.
The quest for single digit bass has myopically ignored how we hear and the dynamic nature of most of what you play and the fact that masking (higher frequencies also in the source material) often hides the lowest frequencies in typical program.
I say that having worked in this area for 20+ years, having developed the Servodrive woofers and other high output systems used in R&D, capable of producing 133dB down to 3Hz (and 175dB up to 30KHz.)

In this case, in a living room, when you use gear like ours, designed for a larger space, there is simply a ton of headroom, something simply not present normally.
You have a speaker with a much higher sensitivity than normal, a “large” power amplifier and a high peak linear output capacity, all of which is loafing along compared to normal use.

Could one put a pile of smaller boxes together, using expensive drivers and lots of power amps that produced the same effect (SPL and response)?
If cost were no object, then while I have yet to run across anything as a product, possibly so, but if a commercial product, the system would be much heavier, much much more costly require much much more power and electricity and have many more places for something to go wrong.
Trading 10dB in sensitivity costs you 10X in increased power required for example.
Keep in mind, unlike home gear, our stuff is installed and left to the whim of the operators etc and hopefully never needs attention.
Also, if I were faced with designing something where output was primary and cost was unimportant, I certainly could make something more powerful.
Given there is nothing like it now in the commercial theater industry, there are probably better things for me to do at the moment.

For the home, now that is another issue altogether, after talking to Ivan about the GTG event and then Brandon and Ricci, I am noodeling something which if it comes to pass should be a significant “home” thumper for the acoustically insane, like me and apparently Brandon , Ricci and others.
I am happy to find that there are more of these folks than i realized.

What the people described at Brandon’s was not the effect of huge deep extension, but having the peak capacity that permits much greater instantaneous peak levels than normal, possible because of the greater acoustic gain in the subwoofer allowing the amp levels to be lower, combined with a big amplifier = headroom.
A lower cutoff is possible, one has to trade either increased size or decreased sensitivity for it.
What many don’t realize is that most “VU” indicator meters are aligned with how loud something sounds, in fact the original VU stood for Volume Unit.
All of these metering systems ignore very short peaks, they do that because very short clipping or limiting is not audible as a discrete flaw like when it’s longer and you obviously can hear it.
Short term clipping is not audible that is, until you can A vs B compare with and without, then the un-clipped signal sounds more dynamic.
Unless your looking at your signals with an oscilloscope, you have essentially no way to know if your reaching instantaneous clipping anywhere in the chain, clip lights normally don’t show it either.
It is unfortunate you weren’t able to hear the TH-50 at Brandon’s GTG because explaining dynamics and headroom capacity isn’t the same as hearing it .
I didn’t hear Brandon’s either but I do have two TH-50’s in my living room, they make a nice stand for the SH-50’s. I can say for the first time in my career in acoustics and loudspeakers, I have never felt like I needed “more”.

Like I said, I am pleased to find others enjoy what I hear in these systems when in the home. I would have never guessed where we got to today, building speakers back in 1970. Bosso, I understand you’re an old time sound industry guy too.
Best,
Tom

KyleLee

05-29-09, 01:11 PM

mjg100

05-29-09, 03:37 PM

otk

05-29-09, 04:00 PM

That is so correct. At the Southern GTG the TH50 blew away all the other subs.

what were the other subs ?

bossobass

05-29-09, 05:56 PM

Bosso - You mention "John's new drivers and PR's" ... do you have a link with specs and pricing available on it ?

Here's the driver, the PRs are also on the site:

http://www.aespeakers.com/drivers.php?driver_id=24

Here's Tack's ported build with some good pics and measurements:

http://www.avsforum.com/avs-vb/showthread.php?t=1141754

Bosso

craigsub

05-29-09, 06:24 PM

Bosso - Thanks !

bossobass

05-29-09, 07:05 PM

You have a real concern about power compression;

It's not that I have any undue concern, it's just a piece of the puzzle to address, along with all of the other factors that need to be addressed in a good HT subwoofers system.

The quest for single digit bass has myopically ignored how we hear and the dynamic nature of most of what you play and the fact that masking (higher frequencies also in the source material) often hides the lowest frequencies in typical program.

Again, in my own case, there's nothing myopic about my approach. The specification calls for 117dB peaks at reference level, within a bandwidth of 3-120Hz. Since, as you're well aware of, the content is never that of single pure sine wave tones, but rather, a complex composition of synthesized and recorded real event tones, the actual requirement for reproduction of single digits is in the range of 105-110dB peaks.

That's the goal. It has nothing to do with my personal thoughts or the way we hear, it's simply the requirement of the format.

Certainly, I could flip a switch to engage a 20Hz HP filter and instantly increase the systems headroom, but that would more appropriately be called a myopic approach, IMO.

Believe me, I laud your accomplishments in the large venue arena in lowering the amplified BW to 20Hz, but in HT, you're leaving quite a bit on the table. Yes, it's argued every day that 20Hz is good enough, equal loudness curves, blah, blah. To each his own. I just prefer to meet the requirement, which I have done for a number of years. To be honest, it was never a matter of a 'chase'. It was actually quite simple.

For the home, now that is another issue altogether, after talking to Ivan about the GTG event and then Brandon and Ricci, I am noodeling something which if it comes to pass should be a significant “home” thumper for the acoustically insane, like me and apparently Brandon , Ricci and others.
I am happy to find that there are more of these folks than i realized.

Excellent! Raising the bar is a good thing, and I can think of no one better for the job. :)

What the people described at Brandon’s was not the effect of huge deep extension, but having the peak capacity that permits much greater instantaneous peak levels than normal, possible because of the greater acoustic gain in the subwoofer allowing the amp levels to be lower, combined with a big amplifier = headroom.

No, what the people there described was the physical assault of 130dB peaks. That required bumping the subwoofer trim by 32X. Although it's certainly a fun exercise, and a true testament to the output capability of the Th-50, it's nothing 8-15s 'crammed into shoe boxes' with 12KW in that room couldn't also accomplish.

The test for subjective detection of headroom would have been to keep the calibration flat and the master volume to reference level and to audition all of the subs with the same source material. I'm sure the TH-50 would have done well in this test because, as you say, headroom is essential, but the two situations are entirely different things.

It is unfortunate you weren’t able to hear the TH-50 at Brandon’s GTG because explaining dynamics and headroom capacity isn’t the same as hearing it .
I didn’t hear Brandon’s either but I do have two TH-50’s in my living room, they make a nice stand for the SH-50’s. I can say for the first time in my career in acoustics and loudspeakers, I have never felt like I needed “more”.

Like I said, I am pleased to find others enjoy what I hear in these systems when in the home. I would have never guessed where we got to today, building speakers back in 1970. Bosso, I understand you’re an old time sound industry guy too.

Yes, in the early 70s, I helped rig Cerwin Vega's "Boogie Barge" floating up the Ohio river in Pittsburgh, which was essentially a river barge full of CV bins, horns and amps. Although the barge was big, it was still cramped to the point of having to occasionally cross in front of that huge blast of sound, which would instantly change your heartbeat to the beat of the music.

I truly would have enjoyed the G2G, as I've been to more than a few over the years. It would be great to hear your subs in an HT situation, but even better if you could attend (hint, hint). :)

Bosso

Ivan Beaver

05-29-09, 08:22 PM

I was under the impression that you had sworn off subs that use high pass filters. The specs for this call for a 20 Hz HP filter @ 24db/Butterworth.

I am the one who put the 20Hz highpass on the spec sheet. And here is the reason.

I agree 100% that the real recommended highpass should be lower than 20Hz.

However the main intended market for the TH221 is large scale sound reproduction-be it either in movies, concerts, theatre, churches etc.

And as such, a very large percentage (like well over 90%-or more) of the digital processors used in those applications have a highpass filter that will only go down to 20Hz. The ones used for home applications simply do not have the features used in those applications.

So to avoid confusion around the product, such as thinking "my processor only goes down to 20Hz, and the recommended highpass is lower than that-so maybe I need to get a different loudspeaker that has a recommended processor setting that my processor can do".

Yes it makes no sense-but many people think like that. The same thought process goes regarding impedance. Many people simply cannot comprehend a impedance that is not 2-4-8-16 ohms. Anything else makes them wonder how well their amp will work with it-as there are no ratings for 3-5-7 ohms etc.

That is why we choose the nearest standard value as the "rated" impedance. AND we also state the lowest impedance AND show an impedance graph. So the educated person can figure out what sort of load they believe the loudspeaker will present to their amplifier.

With a published response graph, you can choose what particular highpass you "feel" is right. And I would argue that a "proper" highpass is also tied to the output level you want out of ANY loudspeaker. At lower levels, no highpass is best, but at high levels if you do not want to tear up your loudspeaker-you better use a highpass.

If I had chosen to say 10Hz HP for the loudspeaker-would any of this discussion even be going on? Would the actual performance of the loudspeaker change? NO.

But somehow a simple stated number has put all sorts of "ideas" into peoples heads-all of which is false.:eek:

Don't try to read to much into it.

At the subwoofer gathering at Brandons house, I used the Danley DSP (4x8), and its highpass only goes down to 20Hz. But I effectively lowered it a bit by using an eq filter at 20Hz and applying a small boost.

The effective freq response was now lower than 20Hz and still flat, because the filter had started to roll off at 20Hz, so the bump flattened that out and a bit lower as well. So the overall EFFECTIVE highpass was more like 16-17Hz.

For every complex question there is a simple-easy to understand-WRONG answer.:D

2100

05-29-09, 08:59 PM

I think the TH-221 is indeed a monster in its own right, along with the new 812 they are the two most capable pro audio subwoofers in existence. But its not going to match 8 LMS's. The B&C's have about 15% of the total displacement of 8 of those LMS so it would be challenging just taking on 4 of them with proper power, at least for short term signals. More so, PR's can be tuned ungodly low without any extra cabinet volume.

I guess we can only compared SPL @ freq figures and not driver/PR Vd, since the real air displacement is much much more at the horn exit due to acoustical gain. :)

Ok I have some time, did some calculations here. You are actually somewhat correct.

Taking CEA-2010 numbers from HTS, the 200L LMS and PR sub gets 114.5dB @ 20Hz 2m, so that's 120.5dB 1m.
4 subs nets you 12dB more, 132.5dB. TH-221 is about 134dB (frm my prev calculations)

40Hz LMS is ~ 4dB more so its 136.6dB. TH-221 is ~ 141dB

70-80Hz range LMS is 137.1-137.5dB lets take it 138dB. TH-221 is ~ 147dB.

8 subs nets you 6dB more, so for 8 LMS 16 PR
138.5dB for 20Hz
142.6dB for 40Hz
144dB for 70-80Hz

For TH-221
134dB for 20Hz
141dB for 40Hz
147dB for 70-80Hz

Bassmaxx uses 3dB power compression for "real world" (as defined in their PDFs).
So TH-221 gunning stuff like trance at full tilt :
130dB for 20Hz
138dB for 40Hz
144dB for 70-80Hz
** I think this very rarely happens for HT program unless you loop the stuff during a demo

Good thing is that the LMS will dig much lower maintaining the SPLs. However I can't calculate how can 8 LMS be cheaper than the TH-221 just for the box/LMS driver/PR. One needs very serious effort and help too during building time as documented in Robertcharles' built. Danley is buy & forget, sorta.

Similar neo-based 21" Driver power compression at -10dB, -3dB and full power :
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=287
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=286

Probably we get a Crest 10001 for the Danley. 4 pcs of Itech-4000 or Crest Pro 9200 for the 8 LMS, or 8pcs of CE4000. (or half that no for 4 LMS) Serious firepower. :D

If one has the dough and space, just get a couple of KYDG BFT-9 which has a knee of about 9Hz for the TH, and be done with it. :D
For me I'll still need some very serious gains from NYSE and local bourse to reach such a stage. :D

Ok...hope the economy gets well soon, then its time for you to release some new drivers!

brandonnash

05-29-09, 09:18 PM

what were the other subs ?

Here are a list of subs with my reviews from the GTG. Click on my sig for the whole thread with reviews, pics, and measuring techniques.
.
.
.
We did testing as straight across the board as we could. We played every sub in the same location so there would be no variation in sound because of room gain/loss from a different placement. We also played the same music and movies with each sub to ensure that nothing was up for discussion about the sub that might've played better with some other music or movies. We also did two separate measurements with each sub. Ricci did a 1 yard measurement directly in front of the sub, mic front pointed toward the driver. Ivan took a measurement close to the opposing back wall of the room with the mic front pointed at the wall to account for room the room itself adding to the sub. I thought the tests and observations were made as fairly as we could do in the amount of time we had with the subs.

Bic H100 - Call it first impressions, but before this sub we only did a few sweeps and pink noise so this was the first subwoofer I heard with music or movies yesterday. Before people started arriving I didn't listen to anything, so when this was played I was actually amazed at the sound coming from this $250 subwoofer. I believe Robert was impressed too because he had to ask 2 or 3 times, almost in disbelief it seemed, that this sub only cost $250. I think it performed very well with music. It seemed like when we started the sub wasn't set to run real hot, so it blended with the main speakers better than some of the rest. With movies it wasn't a huge performer. I think it gave up in the low 30's or upper 20's in room, but it was still very solid. Sounded very good with the Tool track we had on the music cd. This sub got my rating for most shocking (in a good way) of the day.

Outlaw LFM-1 compact - I didn't think this sub did quite as well on music as the Bic, but performed better on movies. I can possibly attribute this to its design. It was a 10" driver opposed to the 12 on the Bic, but the enclosure was larger than the Bic. I've seen that the larger the box the better when it comes to ported subs, up to a point. We had to back the gain down some on this sub at the beginning, but after that it blended very well with the mains. Very clean sound.

ED A7S-450 - When this sub started out we left the same gain with it and could immediately tell that it had much more to it than the previous two subs. It has an 18" driver with a 1300 watt amp in a sealed enclosure. The driver is the same used in my sub, so I was familiar with it's limits and the general sound of it. I thought that in the upper bass it wouldn't do quite as well in quality as the smaller drivers, but in output it could best them easily. The sub seemed much louder than the previous two and that did have an effect on how people judged it I believe. The sub was playing at least 10 dB hotter than the mains, and that contributed to the "muddiness" that I and some of the others may have said about the sound. I run my sub very close to my listening position with zero dB extra over the mains, so when the sub is too loud I notice. In saying this I could tell that if the mains would've been louder, the sub itself would have barely been noticeable. Aside from that I thought it did very well in the music and did pretty well with the movies.

Shiva 12" - When this sub was first brought into my house I could tell it was going to be a performer. Very large enclosure for a 12" sub and dual ports ensured no port noise and a very good response. It's a design that I'm very fond of. I think that trying to cram a driver in a tiny box and throwing a port on it just for output sake doesn't work well most times. I'm waiting for the graphs for this sub as I think it should be pretty good. The sub did great on the music we played and it had some good slam in the movies also. As others have said, we nearly killed the driver with a very hot signal and low frequency signal from "Bass I Love You". After that it performed very well and I think it surprised everyone. At a total build cost of $450 this sub gets my vote for "Best Buy" for the day. Very well made and good professional looking finish to boot.

Audiopulse Epic 12" dual - While others may not have liked this sub, I thought what it was putting out was a very clean sound with music. It was in a small 1 cubic foot per side sealed box, so the sound I was expecting with music was a very tight sound, and it did do that. For movies it had a very steep rolloff in the frequency department, but I attribute that more to the enclosure than the drivers. At $129 each driver, this was a good buy also. It would benefit from a larger sealed, or possibly a ported box to get that extra low end rumble.

ED 190v.2 LLT - This is my sub, so I won't go into too much detail about it. I will say that this is the first home theater sub that I've built and I had my fingers crossed that it was built the way I designed it. The graphs confirmed that tuning was about 15.4 hz and that's almost spot on what I designed it for. I thought I may have needed a bigger port during a couple songs/scenes do to noise, but we figured out it was shaking the door sitting behind it. After hearing the other subs, especially the larger/more expensive ones, I am going to build a better enclosure with a little lower tuning, and will either buy another one to duplicate my first or build another LLT with a better driver.

LMS 18" - This subwoofer was a pleaser. It was in a very small box for the size of the driver, and that is a big plus in most people's books. It had a VERY clean sound. I've heard that that is attributed to the actual LMS design and it delivered a very impressive performance with music and movies. The driver was pushed hard enough at one point that the surround started dimpling, but even at that point it didn't seem to be pushed too hard. The sound coming from the driver was probably the smoothest of all the subs. I'd like to hear this thing in a LLT designed enclosure. It would surely shake the ground. I had very high expectations of this sub. So high in fact I thought I would be let down by the actual sound of the sub, but I was not. Very cool looking driver too.

XXX 18" - This sub was almost as good as the LMS in every category. It surpassed the LMS in output capability, but fell slightly behind in how smooth the sound was. It has seemingly endless excursion capabilities and takes on a new form when it's played loud. Didn't seem stressed at all during movies and music. I would have a hard time deciding between this one and the LMS if I had the option of one, but being that I listen to movies more than music, I would probably choose this one. because of the extra several millimeters of xmax. Highly recommended if anyone is looking for a hard pounding sub to build.

Worx 18" - This is a very unusual driver in that the surround is an accordion shape than the standard surround look. It really put out some SPL's and seems to have very high power handling too. We ran this off the ITECH amp that provides up to 8000 watts. The amp was running off a 220 volt dryer outlet. In movies it didn't have the output down below port tuning, but it still played very loud. It wasn't quite as clean as some of the others, but it did have a very good sound with music. On the movies I could see this sub being a real performer in a commercial movie theater. Line about 4 or 5 of these up in a commercial theater and it would be very loud, even in that large space.

Danley CS-30 - I had pre-conceived notions about this sub. It's a pseudo bandpass subwoofer with a 12" driver, so I thought it would had a very one note sound. I was proven wrong with this sub. It is probably the best designed bandpass sub I've ever heard. The others I have heard have been in either my car or other's cars and they tend to be very boomy. This sub had a sound that was clean. Almost as clean as the LMS. I thought it did great on the music. If I had a dedicated 2.1 channel rig just for music I would choose this sub for that application. It wasn't extremely loud and didn't have the low end slam on movies like the other subs, but that may be because of the bandpass design. Didn't think I would like this sub, but I was very impressed with this sub. Exceeded expectations.

Danley TH-SPUD - This sub is a tapped horn dual 8" driver subwoofer that has several installation options. It can be stood on it's side, or laid down and put a couch on top of it. I wasn't as impressed with this sub as the CS30 in sound quality, but it had it beat in output easily.

Danley Monster Ultra Super Duper Beast TH50 (unofficial name) - I would love to have this sub. I may have to write a more thorough review later, as I could write pages on this sub, even from the short time we had with it. It is a absolutely massive sub that only incorporates a single, albeit a single HUGE 15" driver also in a horn config. Most would think that there is only so much you can do with a single 15, but this thing made me think again. It was the SPL beast and wasn't taxed at all during the testing. At most, I think it was actually only receiving a few hundred watts of power and still managed nearly 130 dB in my 4000+ cubic foot room. It was just as clean as the CS30, if not cleaner, but had it beat in output by an entire universe. This sub finally got me close to the feeling of when I had a blasting car audio system. When sitting at least 15 feet away I could physically feel my clothes flapping. To make this sub the ultimate perfect subwoofer would require 1 more thing, and that's better extension. It still played the 16 hz from bass i love you with authority, but seems like it just wasn't as impressive as the low 20's. I will write more about this sub later, but right now I want to put my room back together.

brandonnash

05-29-09, 09:53 PM

I think this is a great discussion. I value Tom's, Ivan's, Craig's, and Bosso's opinions very highly. If I can have half the audio knowledge obtained by this group in my life I will feel more than accomplished.

I believe that both sides of this discussion have good valid points. Going on what we had at the GTG I don't think there was anyone there that didn't think the TH50 was amazing. If you look at the measurements taken there it shows that, compared to the sealed and even my LLT, the TH50 did drop off earlier, but it wasn't night and day.
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=140362&d=1240278712

For the price of this subwoofer and what it achieves I think it's an all around great value also. Considering that this subwoofer only contains a single 15" driver and manages this kind of performance is outstanding. It has it's drawbacks no doubt (Huge cabinet, somewhat quicker rolloff, etc) but what it was did compared to Bosso's theoretical stack of 15's with 12kw of power for ultimate headroom is solid, no audible distortion, and near 130 db peaks in room with (going on the lights from the amp) somewhere between only 30 and 300 watts. Now if you want to go out and buy 8 15's and enough amps to drive them correctly and build the boxes to go along with them then I say go ahead. It may cost you a lot more $$$ than a TH50 with a single EP2500. From the sound of it, most would probably be happy with the sound if it were driven with the headphone jack of an ipod. It really is that efficient.

That last bit was for crazy bassheads like myself, ricci, and apparently most that are following this thread. For the general public I don't think the TH50 would work, simply because of the size. I think that's where a good properly designed pair of sealed, pr'd, or low tuned ported subs would fit the bill.

This sub took me back to my car audio days when I was driving a small BMW 318i, but with even better sound. For that to happen in roughly ~40x the interior volume for the listening room is phenomenal. I will make a trip down to GA and check out the Demo room there sometime and hopefully there will be a 221 there. I'm not like others in that I don't have the money to buy one or a pair. I wish I did, because I would buy one. Unfortunately for me, I've fallen victim to my own thoughts about "if you had the chance to drink a glass from a $10,000 bottle of scotch and never be able to have it again, would you?" I've tasted what an amazing subwoofer does in my room and it has ruined me from my own subwoofer. I'm in deep thought literally hours a day trying to figure out a way I can achieve that level of quality bass in my room and not break the bank.

allredp

05-29-09, 10:22 PM

I believe that both sides of this discussion have good valid points. Going on what we had at the GTG I don't think there was anyone there that didn't think the TH50 was amazing. If you look at the measurements taken there it shows that, compared to the sealed and even my LLT, the TH50 did drop off earlier, but it wasn't night and day.

For the price of this subwoofer and what it achieves I think it's an all around great value also. Considering that this subwoofer only contains a single 15" driver and manages this kind of performance is outstanding. It has it's drawbacks no doubt (Huge cabinet, somewhat quicker rolloff, etc) but what it was did compared to Bosso's theoretical stack of 15's with 12kw of power for ultimate headroom is solid, no audible distortion, and near 130 db peaks in room with (going on the lights from the amp) somewhere between only 30 and 300 watts. Now if you want to go out and buy 8 15's and enough amps to drive them correctly and build the boxes to go along with them then I say go ahead. It may cost you a lot more $$$ than a TH50 with a single EP2500.

I'm in deep thought literally hours a day trying to figure out a way I can achieve that level of quality bass in my room and not break the bank.

Very cool insights! Others who were at your GTG had similar reports...

Wish I had the $$ and the room for the TH50! Sounds like some serious HT fun.

Dbuudo07

05-29-09, 10:28 PM

mojomike

05-29-09, 11:30 PM

Wow, that's quite a room. What kind of main speakers are you using?

brandonnash

05-29-09, 11:35 PM

I was wondering in a room that's L60' x W45' x H24'...

Wow, that's quite a room. What kind of main speakers are you using?

I don't think he has the speakers or the room yet. It's all being built within the next couple years with an insane audio budget. I've been reading his thread about it for a while.

Dbuudo07

05-30-09, 12:52 AM

Thanks MojoMike. I'm considering the Meyer Sound Acheron 100s with the Acheron LF providing additional headroom for the L, LC, C, RC, R and the HMS-10s for surrounds. Of course I have to do some serious auditioning before any decisions are made. I will include Danley in my list of companies to audition. The room is still being planned, and I'm trying to see how much of it I can plan myself before bringing in the pros.

These Danley monsters are definitely interesting. I'm still learning about the technical aspects and calculations. I have a good grasp of the basics and a bit of the advanced stuff, but I'm nowhere close to the level of guys like Tom Danley, Bosso and Mark Seaton. I really appreciate their posts and other experienced members because they allow people like myself to learn more. I find everytime I read one of these discussions, I spend hours researching. I love it!

Mike Hedden

05-30-09, 08:20 AM

Thanks MojoMike. I'm considering the Meyer Sound Acheron 100s with the Acheron LF providing additional headroom for the L, LC, C, RC, R and the HMS-10s for surrounds. Of course I have to do some serious auditioning before any decisions are made. I will include Danley in my list of companies to audition. The room is still being planned, and I'm trying to see how much of it I can plan myself before bringing in the pros.

If it is possible, please, please, please, do a side by side with us and whomever you wish but especially Meyer, you'll be glad you did.:cool:
At Keith Yates outdoor event the head of Dolby Labs told me he had never heard audio like ours in his life.

Mike Hedden
Danley Sound Labs, Inc.

Mike Hedden

05-30-09, 08:27 AM

I was wondering in a room that's L60' x W45' x H24', what could I expect to get out of a TH 221s below 20 hz? Can I use it in that size room without a HP filter? The room is a sealed dedicated theater by the way.
David,
Our demo room is larger than the one you are describing and we don't use a HP. It is by no means sealed, its just dedicated warehouse space but we have to run folks out of it all the time because it is such a joy to listen and view.
If you really have an interest, we would be glad to design a sub for your room specifically that could be integrated into the room so as to be unseen.
Contact me directly at mike@danleysoundlabs.com if I/we can be of any further assistance.

Thanks,

Mike Hedden
Danley Sound Labs, Inc.

MKtheater

05-30-09, 12:22 PM

Dbuudo07,

Now you have Danley in your corner, take advantage of it.

KyleLee

05-30-09, 10:00 PM

I guess we can only compared SPL @ freq figures and not driver/PR Vd, since the real air displacement is much much more at the horn exit due to acoustical gain. :)

Ok I have some time, did some calculations here. You are actually somewhat correct.

Taking CEA-2010 numbers from HTS, the 200L LMS and PR sub gets 114.5dB @ 20Hz 2m, so that's 120.5dB 1m.
4 subs nets you 12dB more, 132.5dB. TH-221 is about 134dB (frm my prev calculations)

40Hz LMS is ~ 4dB more so its 136.6dB. TH-221 is ~ 141dB

70-80Hz range LMS is 137.1-137.5dB lets take it 138dB. TH-221 is ~ 147dB.

8 subs nets you 6dB more, so for 8 LMS 16 PR
138.5dB for 20Hz
142.6dB for 40Hz
144dB for 70-80Hz

For TH-221
134dB for 20Hz
141dB for 40Hz
147dB for 70-80Hz

Bassmaxx uses 3dB power compression for "real world" (as defined in their PDFs).
So TH-221 gunning stuff like trance at full tilt :
130dB for 20Hz
138dB for 40Hz
144dB for 70-80Hz
** I think this very rarely happens for HT program unless you loop the stuff during a demo

Good thing is that the LMS will dig much lower maintaining the SPLs. However I can't calculate how can 8 LMS be cheaper than the TH-221 just for the box/LMS driver/PR. One needs very serious effort and help too during building time as documented in Robertcharles' built. Danley is buy & forget, sorta.

Similar neo-based 21" Driver power compression at -10dB, -3dB and full power :
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=287
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=286

Probably we get a Crest 10001 for the Danley. 4 pcs of Itech-4000 or Crest Pro 9200 for the 8 LMS, or 8pcs of CE4000. (or half that no for 4 LMS) Serious firepower. :D

If one has the dough and space, just get a couple of KYDG BFT-9 which has a knee of about 9Hz for the TH, and be done with it. :D
For me I'll still need some very serious gains from NYSE and local bourse to reach such a stage. :D

Ok...hope the economy gets well soon, then its time for you to release some new drivers!

ya i guess what we need here is eight 18" LMS's in a tapped horn

:)

2100

05-30-09, 11:33 PM

ya i guess what we need here is eight 18" LMS's in a tapped horn

:)

Unfortunately the LMS5400 / most large X-max type drivers don't really model well for all horns types the last time i played with it. I'm not a horn expert in optimising horns, but if one fine day the a new high X-max type and high-power pro driver gets released, am sure loudspeaker manufacturers or DIYers would take advantage of that.

Of coz the enclosure and driver T/S matters much more for horns, but I guess when we are pushing the envelope for deeper as well as higher SPL in as small a volume as possible without needing crazy efficiencies, Xmax still helps by not being a limiting factor...esp with the power of drivers going up (more cooling too pls!)

Beyma/B&C seems to be on a roll, geez now 21" B&C has 21SW150, 21SW152 and 21SW115, all 15mm The last one is relatively low in cost too but not widely available outside EU. Faital Pro is pushing 12mm, BMS is 19mm for 18N860 i think and Lambda 18 is also pushing 14mm. I know its often a chicken-and-egg situation for both driver and loudspeaker companies. We used to say 9mm is lots for pro-audio. But electronic/synthesized music is trying to dig lower and lower nowadays. Heck what is JBL doing? :D

Love it : http://beyma.com.ua/downloads/News%202009.pdf

Hope your co. is doing well and has some new stuff on the drawing board. *thumbs up*

duwdu

05-31-09, 08:18 AM

dlfromcanada

05-31-09, 09:13 AM

Ivan Beaver

05-31-09, 09:58 AM

Sorry if I missed it having been reported, but were these listening sessions conducted [measured] blind?

Due to the size of the space, only one sub was in the room at a time.

All of the measurements were done indoors-so therefore subject to the room modes. As best as could be done-with the varying size of the subs, the measurement conditions were the same for all. ie the mic was the same distance away (3') from the front of the cabinet. But the mic location in the room changed, due to the distance of the front of the cabinet from the wall.

Yes 3' is way to close to measure a sub, but since this was indoors-it gave a bettter ratio of direct to room response.

The ONLY way to get any sort of real comparitive measurements of subs is outside-well away from all reflective surfaces. This was not feasible in this particular gathering.

You make the best of what you have-and this was a great gathering-thanks again Brandon!

Ivan Beaver

05-31-09, 10:07 AM

a few questions,

if one was considering one of these two monsters for home use, would one provide better sq over the other for music? would it be better sq than a th50? does Danley build the amps into the enclosures for the powered versions? finally, are these the types of subs where a single unit could be placed anywhere in any normal sized room and get killer bass at any listening position?

I guess I'm basically wondering if one of these units could be my plug and play, set it and forget it, holy grail for the next 20 years, because if so, it would seem like a hell of a good deal

On the powered versions (Danley offers both powered and non powered on almost all of their products) the amps are built into the cabinets. The 3 cabinets in question are all available powered.

I have not spent much time listening to the difference in sound quality of the different units. They are all designed for different applications. Let's say one does sound better (and exactly what does that mean?-it means different things to different people:rolleyes:) but will not physicaly fit into your room, or does not go low enough for your needs, or does not get loud enough etc-then is it a "better" sub FOR YOU? The usual answer-IT DEPENDS. Different people have different needs/desires.

Regarding room placement, the room will ALWAYS be a dominating factor-especially in the lower freq.

There are no-and will never be, a sub that you can put anywhere and have the same sound everywhere. UNLESS you make the room very small-such as in a car. Now you have moved from the modal zone-to the pressure zone, in which the sound will be the same-at the lower freq-but not at the higher freq.

It is all a tradeoff. Physics still wins.

Hope that helps some.

brandonnash

05-31-09, 07:14 PM

Ivan Beaver

05-31-09, 08:58 PM

I'm already thinking of a meet for next year too. I may try to make a weekend out of it so we won't have to cram everything in. We had a really good flow to the day, but I would like to have more time with each subwoofer. Maybe if I take everything off the walls and shelves and bolt down anything that's on the floor we could have on of the 221's here. That would be craziness.

What kind of application are you wanting ideally with the 221? I think you said it's the equivalent of 4 th50's?? So in having this being the same as 4 of the 50's you could possibly power a whole IMAX theater with 1 enclosure? If you install anything in Nashville's IMAX I will break my 7 year streak of not going to the movies and check that out.

Since I'm still learning about horns, specifically tapped horns, with low end frequencies below the load of the horn, would the driver and enclosure unload like a ported box? If I were to watch something like WOTW at a good volume what would the risk be of damaging the drivers if it tried to play the lightning strike scene?
If you do it again remember I won't be able to fit a TH221 into my van-so would have to bring a trailer. Maybe I could also bring some larger LCR main cabinets for greater output.

You also need to remember that this cabinet will do 140dB+ OUTSIDE! Inside with room gain???

The current version of the 221 is targeted for touring type people who want to go down real low and still have lots of punch to the music. Of course it could easily be for installs in larger rooms (or smaller ones that want to get loud):eek: Yes it will fit through your door.

I have feeling IMAX will get getting ahold of these.

Yes the driver will unload when driven hard enough and low enough. The Tapped horn presents a lot of control over the driver and it does not move much-untill you get near the max output. In the demo room we do not run a highpass on it, but are also not powering it up to full potential. We only have a little over 3,000 watts to put to it.

We have not run out of amp or excursion yet.

In a room even quite a bit larger than yours, I doubt you would have any issues.

Ricci

06-02-09, 01:57 PM

Ricci

06-02-09, 02:38 PM

Now, you refer to Illka, I have seen his testing procedure and it is logical for what he’s trying to get to (maximum sustainable level limited by THD or amp limiting).
Also, from what I understand he decided to do this on his own so I am not sure how his level of information compares to what hifi subwoofers come with as in spec sheet.
I don’t know if he is still doing these tests but maybe it would be fun to send a box or two to him to measure that way. It will be interesting to see if he can get the cops and neighbors to offer their opinions..

I actually mentioned your products to Illka long before I'd ever heard them and suggested the DTS20 or TH50. Being that he's in Finland and also employed by Genelec now I don't know how likely that is to happen but, it'd be very interesting to see the results...

What the home theater focus seems to miss I think is that much of what we listen to is not a sustained signal but has large changes in level which also represent low frequency content.
The quest for single digit bass has myopically ignored how we hear and the dynamic nature of most of what you play and the fact that masking (higher frequencies also in the source material) often hides the lowest frequencies in typical program.
I say that having worked in this area for 20+ years, having developed the Servodrive woofers and other high output systems used in R&D, capable of producing 133dB down to 3Hz (and 175dB up to 30KHz.)

In this case, in a living room, when you use gear like ours, designed for a larger space, there is simply a ton of headroom, something simply not present normally.
You have a speaker with a much higher sensitivity than normal, a “large” power amplifier and a high peak linear output capacity, all of which is loafing along compared to normal use.

Could one put a pile of smaller boxes together, using expensive drivers and lots of power amps that produced the same effect (SPL and response)?
If cost were no object, then while I have yet to run across anything as a product, possibly so, but if a commercial product, the system would be much heavier, much much more costly require much much more power and electricity and have many more places for something to go wrong.
Trading 10dB in sensitivity costs you 10X in increased power required for example.
Keep in mind, unlike home gear, our stuff is installed and left to the whim of the operators etc and hopefully never needs attention.
Also, if I were faced with designing something where output was primary and cost was unimportant, I certainly could make something more powerful.
Given there is nothing like it now in the commercial theater industry, there are probably better things for me to do at the moment.

What the people described at Brandon’s was not the effect of huge deep extension, but having the peak capacity that permits much greater instantaneous peak levels than normal, possible because of the greater acoustic gain in the subwoofer allowing the amp levels to be lower, combined with a big amplifier = headroom.
A lower cutoff is possible, one has to trade either increased size or decreased sensitivity for it.
Best,
Tom

Speaking for myself alone. . .Having grown used to hearing the very lowest freq's be at least represented in some sense in my home systems I can tell when they are missing on familiar material. At least I like to believe that I can. Having been a long time musician and around PA type gear for years I've also grown used to what having the headroom that you speak of in the "regular" music range >40hz sounds like as well. a truly bad bass system has neither extension or headroom. The holy grail for me is the system that has more headroom than I'll ever need all the way down into the deepest bass. DSL is one of very few sound companies that I can think of making large advances toward that goal with products like the TH50 and TH221, which combine sound reinforcement type efficiency and headroom while maintaining it all the way down into the 20hz range. That's why so many people go DIY. It's not just about saving money, or being hands on, or learning, it's also about achieving something that most of the companies out there just don't offer a realistic solution for. On the flip side of that I may be commiting a cardinal sin here, but at somepoint you truly can have more than enough headroom like a TH221 on a 6KW amp in your living room. This may be different for everyone, but at some point I'm willing to sac some ultimate efficiency and peak output for more extension. Some people may only wish to have headroom for clean 115db peaks. Having my background I'd like to have more like 125-130db peak capability just in case and so that everything at normal, sane levels is well within system limits and with as low distortion as possible.

KyleLee

06-02-09, 04:53 PM

Due to the size of the space, only one sub was in the room at a time.

All of the measurements were done indoors-so therefore subject to the room modes. As best as could be done-with the varying size of the subs, the measurement conditions were the same for all. ie the mic was the same distance away (3') from the front of the cabinet. But the mic location in the room changed, due to the distance of the front of the cabinet from the wall.

Yes 3' is way to close to measure a sub, but since this was indoors-it gave a bettter ratio of direct to room response.

The ONLY way to get any sort of real comparitive measurements of subs is outside-well away from all reflective surfaces. This was not feasible in this particular gathering.

You make the best of what you have-and this was a great gathering-thanks again Brandon!

I'm gonna agree, however not in all cases, some subwoofers (usually not pro audio) are designed to to coupled to a wall, room or corner in some way shape or form. Big pro audio speakers are generally designed such that all ports and drivers fire in one direction.But if we have for example, side or rear firing ports or passive radiators, then outdoor measurement becomes challenging. For example, if i have a rear firing port, i might measure 100dB outside, but then with 1 wall behind it, i might get more than 6dB increase from the original measurement, and if this is to be used in a room, we don't really care about the free space or half space measurement as much.

Ricci

06-02-09, 05:27 PM

brandonnash

06-02-09, 07:40 PM

Make sure that you let me know if you do. I'll be there and I'll make plans to bring bigger artillery than last time;)! Saturday and Sunday both with Friday night preparation sounds like a plan.

Bigger artillery?? Whatcha got bigger? Are you hiding some 21"ers somewhere, or maybe just a simple 15kw amp? This is still a thought and a long way away for another sub shootout. I'll most definitely have it in the winter so we won't encounter the same extreme temps in room. Having this stuff going on with the windows open in 40 degree temps will cool the room off nicely.

I actually mentioned your products to Illka long before I'd ever heard them and suggested the DTS20 or TH50. Being that he's in Finland and also employed by Genelec now I don't know how likely that is to happen but, it'd be very interesting to see the results...

I would like to see these measured in the same way Illka did his test. Wasn't someone else planning on taking over his role? If it can't happen over there I wonder if someone here could perform those duties. I would volunteer, but I don't have the correct measuring equipment. I have the time to though. If anyone around the Middle TN area has the equipment let me know and we'll try to set something up.

Speaking for myself alone. . .Having grown used to hearing the very lowest freq's be at least represented in some sense in my home systems I can tell when they are missing on familiar material. At least I like to believe that I can. Having been a long time musician and around PA type gear for years I've also grown used to what having the headroom that you speak of in the "regular" music range >40hz sounds like as well. a truly bad bass system has neither extension or headroom. The holy grail for me is the system that has more headroom than I'll ever need all the way down into the deepest bass. DSL is one of very few sound companies that I can think of making large advances toward that goal with products like the TH50 and TH221, which combine sound reinforcement type efficiency and headroom while maintaining it all the way down into the 20hz range. That's why so many people go DIY. It's not just about saving money, or being hands on, or learning, it's also about achieving something that most of the companies out there just don't offer a realistic solution for. On the flip side of that I may be commiting a cardinal sin here, but at somepoint you truly can have more than enough headroom like a TH221 on a 6KW amp in your living room. This may be different for everyone, but at some point I'm willing to sac some ultimate efficiency and peak output for more extension. Some people may only wish to have headroom for clean 115db peaks. Having my background I'd like to have more like 125-130db peak capability just in case and so that everything at normal, sane levels is well within system limits and with as low distortion as possible.

Before the GTG I thought headroom was just a way that crazy bassheads tried to justify their multiple 18" several thousand watt systems. I've since learned about headroom a lot more and I would say I'd like headroom potential up to at least 125 db levels. I know a lot of people would say "why do you need so much?", but I noticed that when my subwoofer was going at full bore 115 or higher db it didn't sound that good. It was sounding stressed. Yes, it can play reference levels for just about any movie minus the ones with EXTREMELY low frequencies (10 hz and down), but it's running at max capacity by that point. Run a car at 9000 RPM for an extended length of time and you lose all kinds of potential. It may have zero room for improvement in top speed (high end SPL's), zero room for acceleration (dynamics) and the engine may start to break down (distortion or bottoming out). Increasing the amount of drivers and power will let them run a lot more clean and keep all those other little extras that we all want.

This is my goal. More headroom. Deeper extension wouldn't be bad either, but headroom is my goal for the future. I want that headroom in my subwoofer first and then I'll add on my mains to try to keep them up. More efficient mains and possibly even some very efficient pro audio mains are in the cards, as long as the quality can keep up too.

bossobass

06-02-09, 10:01 PM

I'm gonna agree, however not in all cases, some subwoofers (usually not pro audio) are designed to to coupled to a wall, room or corner in some way shape or form. Big pro audio speakers are generally designed such that all ports and drivers fire in one direction.But if we have for example, side or rear firing ports or passive radiators, then outdoor measurement becomes challenging. For example, if i have a rear firing port, i might measure 100dB outside, but then with 1 wall behind it, i might get more than 6dB increase from the original measurement, and if this is to be used in a room, we don't really care about the free space or half space measurement as much.

I've always agreed with this line of thought. Comparing a close mic measurement to verify the FR and a measurement at the listening position to determine the transfer function of the specific room it will perform in is more important than outdoor measurements of FR, power compression and total harmonic distortion.

I've always designed subwoofer systems with versatility in mind.

CJ's results with the PB13 Ultra and PC 13 Ultra verify, IMO, the discrepancy in the tests between a front firing sub and an identical-in-every-other-way down firing sub.

He also correctly describes how the differences in output, in room vs outdoors, renders the THD numbers all but useless.

He also describes and shows results of the huge difference in group delay between indoor and outdoor measurements of the same subwoofer.

Power compression graphs from outdoor measurements will also be useless indoors. PC can easily be ascertained in-room and is solved by multiples.

Frequency response, again, is useless from a one-response-fits-all perspective, since, obviously, one response may work well in room 'A', but sound lousy in room 'B'.

Outdoor measurements are for comparing the anechoic FR of and how loud a slow sine wave sweep can be played by sub 'A' vs sub 'B', but they give little information as to how a sub will perform in 'X' room.

Just look at the response graphs posted above from the G2G. It's hard to distinguish one from the other. One may have been perceived as handling a particular movie scene better than another simply because one exhibited a 10dB hump in the specific BW of the sound effect while the other showed a 5dB dip in the same BW.

There are 30+dB swings in in-room response in those graphs. Cranking such a response to levels that swamp all sense of accuracy doesn't do much in reality for accurate presentation.

GP measurements are fun to look at and squabble over, but I recall Ilkka e-mailing me to declare, "The Tumult is a bad driver." after his test of one. Right.

Bosso

Tom Danley

06-03-09, 12:03 AM

Hi guys
A few thoughts
Don’t be so quick to dump half space measurements.
There are two good reasons to measure in half space.

First, it is the best and maybe only way of measuring what the speaker does, that is important when designing a speaker or when specifying what it does because when you put it in a room, the room’s transfer function alters the response the subwoofer produces.
You can see that it is the room transfer function and not the room altering the subwoofer itself because you can interchange the location of a subwoofer and microphone and get essentially the same measurement, that is, the speaker response altered by the room transfer function.

An exception would be for a bass horn, in addition to the fractional space change, if a horn is tailored to the expansion rate coming out of a corner, then in this case the room actually does alter the speaker by adding an additional horn segment.
This is not at all as simple as “putting one in the corner” however as horns have a “high pass” filter effect which is dependent on the rate the area expands.
Also, if one were to move a ported box close enough to the wall that the port is partly occluded, then it is also altering the speaker response.
Other wise, the room really doesn’t normally change what the subwoofer does, it hugely changes what reaches your ears a couple meters away via room transfer function.

Secondly, as people have noticed some configurations produce different readings, for example down firing was mentioned. In a room, this spatial distortion can be so severe that even a small change in position of either the speaker or microphone or even moving large items in the room like other speakers, can alter this transfer function.
Even bringing an un-powered (disconnected) subwoofer into a room, can alter the measured in room response of the one your measuring.

Basically, in room comparisons are relative to that set at best and best done using the exact same locations for mic and each sub AND keep the other disconnected subwoofers as far away as practical. If they have to be there, short the terminals of the un-powered ones. Remember, an un-powered subwoofer is a Helmholtz absorber.
This is why outside is the way to go so far as measuring what the speaker does relative to the design and why one has to re-measure and eq once it is in the room.

There are at least two problems measuring “up close” too.
The enclosure itself takes up some of the space which in the assumption should be radiation space. This means that if one started measuring the sub at say 100 meters and moved closer, one would find the inverse square law at work, at work until your close enough for the spatial distortion to alter the reading “up close”.
For the truly hard core, one can of course excavate a pit so that the subwoofer can be mounted flush and acoustically correct…….or just move a bit farther away and correct for the distance relative to “one meter”.

Second, the issue of pseudo sound near a high velocity low frequency source.
We assume / depend on the microphone element being displaced proportional to the pressure alone, air has mass, at the port outlet for example, one has high velocities.
If the microphone is near a local velocity source like a port, some of the reading is due to pressure and some is due to the kinetic reaction of the air molecules bouncing off the diaphragm. This is “pseudo sound” a measured pressure, which does not show up farther away or in the inverse square fall off (it is not sound per say).

In each case, the remedy is to measure farther away with either intense or physically large sources if an accurate measurement of the speaker is desired.

Same is true for group delay and distortion.
For distortion, if you measure that inside, you are including all the room noises that you can and can’t hear, these are level dependant so it will make the louder of two subwoofers measure more distortion even if it wasn’t producing it.
Illka’s approach of doing it outside also makes a lot of sense IF being able to compare various subs to each other was the goal (and obviously was).
Group delay, same here, the group delay the speaker has is unchanged when you put it in a room, what changes is the room transfer function altering what happened between the speaker and microphone.
Bosso, I don’t remember the Tumult being a bad driver, at the time, it was a “bad” driver in a good way.
Best,
Tom Danley

michael hurd

06-03-09, 01:44 AM

Good post Tom, I would like to pose the following question, what does a microphone measure, pressure or velocity? ;)

Tom Danley

06-03-09, 11:10 AM

Hi Michael

You ask a good question.
What does a microphone measure, pressure or velocity?

Well there are both kinds of microphones, ones which are designed to be “Velocity” microphones and ones which are “Pressure” microphones.

An example of a Velocity microphone is an old style ribbon mic.
This was a VERY thin metal foil ribbon, running through a strong magnetic field.
This is exactly like a true ribbon loudspeaker but much smaller and in reverse.
Both front and back are open, the stiffness of the foil is VERY low so the mechanical resonance is at a very low frequency, making the ribbon very easy to move (and damage).
With such low mass, the ribbon is swept along by the sound’s air motion and being a conductor in a magnetic field, produces a voltage proportional to the conductor velocity, hence "velocity microphone".
The down sides of this are the easy to damage nature of the ribbon and that the ribbon while small is still large enough to exhibit frequency dependent “directivity” which is not desirable in a measurement mic.

An example of a pressure microphone would be the most common mic a one sided condenser microphone.
Here sort of an opposite strategy takes place.
One has an acoustically small diaphragm, small so that it has no directivity.
This diaphragm is loaded into a very small air volume, usually it is the tiny air gap between the diaphragm and the pickup plate.
With the air gap being SO small and the diaphragm being so thin and light, the Fb or resonance for this is ideally above 20KHz.
The pickup plate is an insulated disk right under the diaphragm, in some modern and all old condenser mic’s, this plate was polarized at 48 to 200Volts DC though a “huge ohm” resistor.
The air gap separating the plate charged with a DC voltage and the metalized diaphragm at ground potential forms a capacitor. Now, when a “sealed box” speaker like the microphone is operated below it’s Fb, one finds the displacement of the diaphragm is proportional to pressure, independent of frequency.
By attaching a tube grid or Fet gate coupled through a capacitor to the plate, one finds the Voltage on the plate is pushed up and down exactly proportional to the diaphragm motion and here one has a microphone who’s output voltage is proportional to the pressure.

There are other kinds of microphones, many have directionality, non-flat response or responses which change with distance. The are to solve particular problems and at times unavoidable consequences of one approach or another. For measurements these are not useful.

Also, like I mentioned earlier, there is the issue of Psuedo sound.
I worked on a vary large sound cancellation project in the late 80’s where a huge amount of effort went into solving a problem based on measurements which included this pretend sound energy which was an artifact of the local kinetic motion and not radiated air pressure IE; sound you could hear / measure at a distance.
Ironically, the sound cancellation system had been in operation for only a few weeks when the Redondo beach earthquake knocked the plant off line for a long time and the project forever.
This was a kind of cool speaker too, a giant rotary vane sort of like the Phoenix Cyclone with the displacement of 6 X 18 inch drivers at 1.5 inches p/p. The 20 foot diameter fan required 8 of these drivers around it’s periphery, each one had a 5Kw servomotor amplifier driving it, as the working air was like 150 degrees, each motor had forced air cooling.
Anyway i am running on, I better get back to work.
Best,
Tom Danley

penngray

06-03-09, 11:22 AM

If it is possible, please, please, please, do a side by side with us and whomever you wish but especially Meyer, you'll be glad you did.:cool:
At Keith Yates outdoor event the head of Dolby Labs told me he had never heard audio like ours in his life.

Mike Hedden
Danley Sound Labs, Inc.

David, definitely give Mike, Tom and Danley Sound Labs a chance!! They do not mess around with their products, imo they do not care about BLING, they care about pure, raw performance. It would be my choice (or custom Seaton designs) if I didnt love building my own speakers so much.

Ricci

06-03-09, 12:30 PM

Bigger artillery?? Whatcha got bigger? Are you hiding some 21"ers somewhere, or maybe just a simple 15kw amp? ..

Well...the subs I brought last time were sealed. I do have a 3X in a ported cab;).

I would like to see these measured in the same way Illka did his test. Wasn't someone else planning on taking over his role? If it can't happen over there I wonder if someone here could perform those duties. I would volunteer, but I don't have the correct measuring equipment. I have the time to though. If anyone around the Middle TN area has the equipment let me know and we'll try to set something up. .

There was talk of someone new starting up something similar to Illka's tests here in the states but it fell through. Illka has repeatedly said that he's going to continue but it's been quite awhile since we've heard anything from him. AVtalk still does some but they don't do the DIY thing. I thought about it. I have a central US location and access to a warehouse with a very large field on one side in an industrial park, but I don't really have the time available and I'd have to invest in some better measuring equipment, plus do some more learnin on the subject.

Ricci

06-03-09, 12:34 PM

Tom,

Am I right in thinking that measuring a PR'd, downfired, or ported sub outside at a greater distance like 10m would help mitigate the effects of having the driver and resonator on opposite faces of the enclosure compared to a much closer 1m, or 2m measurement?

Dbuudo07

06-03-09, 05:36 PM

I'd like to thank Mike Heddon and Soundood for the info they've provided me with as well as the invitation to audition your equipment. Very helpful indeed. You've given me more to think about. Thanks penngray. I definitely will make my way to Georgia during my road trip of auditions to experience what Danley has to offer.

brandonnash

06-03-09, 10:33 PM

Thanks for the graphs Brandon.

Obviously there are issues discussed here that are way over my head; but just looking at the FRs, I would expect either the ED190V.2 or the Worx TL118 to sound the best/cleanest, and may be loudest in totality.

From a FR graph I would say yes, but that wasn't the case. Easily the best sounding subs there were the LMS over the XXX by a slight margin, and of course the TH50. The LMS and XXX could really dig down and I think in a large ported box or eq'd sealed box these could really hit some extremely low notes at a high db level. My 19Ov.2 wasn't nearly as clean sounding as a lot of the others. The TL118 had some great output for a sub it's size. It just seemed that once it got up into higher spl levels it didn't sound quite as clean. For what you're going for I still think that, like others have said, a properly designed room first and then a ton of subwoofers that can really dig deep. If the TH221 sounds as clean as the TH50 and drops the extension down a bit it should be the ultimate HT subwoofer. From the sensitivity alone you could run it off of a headphone jack from an Ipod and still get output most subs would get from several hundred watts of power.

bossobass

06-04-09, 12:59 AM

Anyway i am running on, I better get back to work.
Best,
Tom Danley

Tom,

More running on is fine with me. I could read your stories all day. :cool:

Of course, you bring up a good point in measuring ported/PR'd subs. I tend to forget the problems associated with that because I don't have occasion to have to deal with it.

OTOH, here's an example of indoor measurements with a sealed sub, which is what I've used for quite a few years. I use the close mic measurement vs a listening position measurement to configure the Linkwitz Transform, then a second LP measurement to confirm or further tweak the L/T.

The 3 traces are the close mic and the final L/T (also close mic) and LP measurements.

I'm wondering what's missing in the close mic measurement that an outdoor GP measurement would reveal, for this particular exercise?

http://i469.photobucket.com/albums/rr55/Bosobass/lpcopy.jpg

Bosso

Tom Danley

06-04-09, 01:05 PM

Hi Ricci, Bossobass, all

Ricci, yes you are right, moving farther away will reduce all of the errors like that.
A rough rule of thumb might be that one should be 5 to 10 times the distance between all the sources and or box dimensions.
In many cases 2 or 4 meters would be sufficient and to get the equivalent “1W1M” sensitivity without adjustment, requires a drive voltage 2 times and 4 times the nominal.
We use 10 meters usually because the boxes are even larger and 10X the voltage, 10X the distance is easy to keep track of.

If you guys are thinking of maybe doing this kind of testing (like Illka was doing), I think we might be able to help some. His methodology seemed logical and proper for making comparisons.
Brandon, Ricci, things are “proceeding” btw.

Hi Bossobass

“The 3 traces are the close mic and the final L/T (also close mic) and LP measurements.
I'm wondering what's missing in the close mic measurement that an outdoor GP measurement would reveal, for this particular exercise?”

Well so far as an aid to blending it into your room in question, the 1 meter data would be of little or no help.

If you were at the design stage, half space data would allow you to know a number of additional things.

Such as the subwoofer system’s actual frequency response which one could use to compare to a predicted computer model of same (which normally assumes a half space radiation).

Such as the 1W1M sensitivity in either Watts or Voltage reference.

Also, if one had the actual frequency response and sensitivity, one could subtract it from the “in room” response and get the difference or room transfer function.

Bosso, do you work for a speaker or driver company? Your too deep into this to be a “casual dabbler” it would seem.
Best,
Tom

brandonnash

06-04-09, 01:22 PM

If you guys are thinking of maybe doing this kind of testing (like Illka was doing), I think we might be able to help some. His methodology seemed logical and proper for making comparisons.
Brandon, Ricci, things are “proceeding” btw.

I'd like to see some testing like this. If I could help out it would be even better. I'm just not really close to anything out my way. I do have access to a 35 acre field 5 minutes down the road from me that's very open except for a very few cows.

I'm looking forward to what you come up with on the "proceeding" item.

Ricci

06-04-09, 02:20 PM

Hi Ricci, Bossobass, all

Ricci, yes you are right, moving farther away will reduce all of the errors like that.

Tom

Ah. I thought so.:)

If you guys are thinking of maybe doing this kind of testing (like Illka was doing), I think we might be able to help some. His methodology seemed logical and proper for making comparisons.
Brandon, Ricci, things are “proceeding” btw.

Tom

I would like to see someone start 3rd party testing here in the states for commercial/DIY/pro subs. Illka was in Norway which presented logistical issues sometimes and he may no longer have time to do the tests. I'm trying to convince myself that I have the time and werewithall to do it.:rolleyes:

That's great news. Drop me an email when you have you feel like sharing an update.

Bosso you said
“The 3 traces are the close mic and the final L/T (also close mic) and LP measurements.
I'm wondering what's missing in the close mic measurement that an outdoor GP measurement would reveal, for this particular exercise?”

For setting up ones own sub in room not much, but for comparing greatly differing subs to each other outdoors , GP makes perfect sense to me. It keeps the playing field level. If one sub has greater headroom, extension and vastly lower distortion levels outdoors, over another sub, the same will be true indoors as well.

It's nearly impossible to get things exactly the same indoors. At Brandon's GTG we tried to get things positioned as closely as possible but the shapes, sizes and configurations of the various subs prevented this. Obviously things weren't exactly level matched and double blind and there were a million things that weren't right for us to compare things directly head to head. Even still since there was such a broad range of subs, there it wasn't very hard to tell what the relative strengths and weaknesses of each were. Next time we'll do better.

bossobass

06-04-09, 08:19 PM

Hi Bossobass

“The 3 traces are the close mic and the final L/T (also close mic) and LP measurements.
I'm wondering what's missing in the close mic measurement that an outdoor GP measurement would reveal, for this particular exercise?”

Well so far as an aid to blending it into your room in question, the 1 meter data would be of little or no help.

If you were at the design stage, half space data would allow you to know a number of additional things.

Such as the subwoofer system’s actual frequency response which one could use to compare to a predicted computer model of same (which normally assumes a half space radiation).

Such as the 1W1M sensitivity in either Watts or Voltage reference.

Also, if one had the actual frequency response and sensitivity, one could subtract it from the “in room” response and get the difference or room transfer function.

Thanks again for the insights, Tom. The 1W/1M sensitivity is interesting to me. Is that an average of the FR magnitude results of your outdoor measurement?

Bosso, do you work for a speaker or driver company? Your too deep into this to be a “casual dabbler” it would seem.
Best,
Tom

No, but if that's a job offer, I'm on my way. :D

Bosso

bossobass

06-04-09, 08:38 PM

Ah. I thought so.:)

I would like to see someone start 3rd party testing here in the states for commercial/DIY/pro subs. Illka was in Norway which presented logistical issues sometimes and he may no longer have time to do the tests. I'm trying to convince myself that I have the time and werewithall to do it.:rolleyes:

That's great news. Drop me an email when you have you feel like sharing an update.

Bosso you said
“The 3 traces are the close mic and the final L/T (also close mic) and LP measurements.
I'm wondering what's missing in the close mic measurement that an outdoor GP measurement would reveal, for this particular exercise?”

For setting up ones own sub in room not much, but for comparing greatly differing subs to each other outdoors , GP makes perfect sense to me. It keeps the playing field level. If one sub has greater headroom, extension and vastly lower distortion levels outdoors, over another sub, the same will be true indoors as well.

I liked to kid Ilk that he was in the North Pole, but actually, he's in Finland, where his new employer is HQ'd.

Unless someone succeeds in convincing the industry as a whole that 2M GP outdoor measurements should be a universal standard, you'd better get busy.

Between Mullen, CJ and Ilk, they haven't scratched the surface of the available subs to measure, if comparison from one to the next is the goal.

Actually, Nousaine has measured more subs than the 3 of them combined, and he measured all of them... indoors.

From Keith Yates' WWD article:

1. Conduct the tests outdoors, including the listening tests. This eliminates room gain, which enables any sub to play louder in a room, with lower distortion, than it can outdoors. However, testing outdoors also eliminates destructive subwoofer/room interactions, including room modes that vary from space to space. [emphasis added]

Of course, outdoor measurements have advantages, but the ultimate use is indoors. Yes, all rooms have a sonic signature, but why ignore that fact and leave the end results to the sub owner to struggle with? The in room vs anechoic differences should be the focus of attention, not brushed aside as some sort of unconquerable realm.

Room modes and room gain, once the mystery nemesis, aren't all that mysterious.

Concentration on anechoic performance skews the design goals to the detriment of end use, IMO. At least offering versatility with end use in mind is better than designing to win the 2M/GP drag race, no?

Velo's digital drive, Brian's multi-tune/multi-Q and TV's multi-tune ported designs come to mind. My subs have infinitely variable tune and Q options, which absolutely help in dialing in the end result.

Mostly, with the exception of multiple tests of the various tunes of the SVS models, the outdoor tests only pick one option to test.

Bosso

Tom Danley

06-08-09, 10:54 AM

Hi Bosso, all

Bosso, you had asked;
“Thanks again for the insights, Tom. The 1W/1M sensitivity is interesting to me. Is that an average of the FR magnitude results of your outdoor measurement?

Unfortunately in addition to being a measurement and specification, 1W1M sensitivity is a sales tool and is often “stretched” for maximum effect. Like power handling and maximum output, sensitivity figures may not be what you actually measure.

For example, once a subwoofer system has become large, usually using multiple drivers or horn loading, then one finds that the frequency response is not flat but tipped upwards.
The physical size alone is one way that a system can produce frequency dependant directivity but also drivers can do this via a broad breakup region.

Now, all too often in commercial sound, a subwoofer’s sensitivity is given as one number and most of the time subwoofer mfr’s do not have a measured response curve.
In one humorous case of a big name (three letter) company the response is given and from that one can see that the sensitivity figure was taken at 300Hz and if one were using it as a subwoofer as intended, then the actual sensitivity is more like –9dB from the “number” they give.

Because so many of our sales are to systems, which others have designed, we try to give more than average amount of information.
That is why we have real response measurements, done in a conservative way that others can replicate and that gives valid data for system designers.

If you look at the sensitivity spec, we often call out more than one number corresponding to frequency. With most subwoofers, all with no curves, one has no idea what the sensitivity is at say 20, 30, 40 Hz etc, especially if the “number” was taken at say 800Hz as was another big name California subwoofer.

We have been told that the appearance of actual TEF measurements, particularly for full range speakers is going to scare away some people but the system designers and engineers say please don’t stop.
I suppose if we do get into home audio more, we will have to have less but prettier measurements commensurate with what folks are used to when present at all.

It does not appear the situation is much clearer in home audio, few sub mfrs seem willing to show the basic response curve and sensitivity while there is a lot of talk about maximum loudness, there is little reference to how that was measured and in room measurements are nearly useless for comparisons in other rooms or other room locations.

“From Keith Yates' WWD article:
Quote:
1. Conduct the tests outdoors, including the listening tests. This eliminates room gain, which enables any sub to play louder in a room, with lower distortion, than it can outdoors. However, testing outdoors also eliminates destructive subwoofer/room interactions, including room modes that vary from space to space.
[emphasis added]

Of course, outdoor measurements have advantages, but the ultimate use is indoors. Yes, all rooms have a sonic signature, but why ignore that fact and leave the end results to the sub owner to struggle with? The in room vs anechoic differences should be the focus of attention, not brushed aside as some sort of unconquerable realm.

Room modes and room gain, once the mystery nemesis, aren't all that mysterious.

Concentration on anechoic performance skews the design goals to the detriment of end use, IMO. At least offering versatility with end use in mind is better than designing to win the 2M/GP drag race, no?”

Well yes and no.
First, I consulted with Keith on doing these measurements, have designed an Uuber Sub with a 9Hz corner and full range theater speakers for him and I had designed the contrabass he tested once so there is potentially some contamination haha.

A few thoughts,
If one had ten different subwoofers with identical response shapes and cabinet sizes and you measured them in half space and ranked them according to maximum output, you would find that the strongest one out doors was also the strongest one indoors and so on.
The room doesn’t effect which one is the most powerful.
If you took ten subs which all had different low corners, the one with the lowest cutoff out doors will also have the lowest cutoff indoors.

If you took one subwoofer and placed it in a room, you would find the response has significantly changed and is different everywhere you measure. If you took that same subwoofer and measured it in a different room, you would find another set of different response curves.

If you had used a fixed drive level and measured the radiator motion or internal pressure during all these room tests, you would find the room has essentially no impact on the actual operation of the woofer, in reality the room effects what happens between the speaker output and microphone.
Since when you measure outside, you see only what the speaker is doing, it provides more information than measuring inside where even a small change in position, subwoofer shape or configuration can produce wildly different measurements.

I guess the way I see it is that everyone’s room will greatly alter what reaches the microphone, even in that same room, changing the location of the mic or speaker will alter that too.
What everyone’s rooms will do is different.
That has no bearing on what an optimized subwoofer design looks like measured in half space, does not ‘invert” any thing so far as desirability, distortion, cutoff etc..
What you can get in a room is a matter of placement, speaker capacity and EQ, that is to say making the best of what your individual room (and speaker /listener location)does..

All that being said, bass Horn systems, being an acoustic coupler DO feel the room to a varying degree and appear to drive the additive modes somewhat less strongly.
Best,
Tom Danley

bossobass

06-08-09, 04:46 PM

Well yes and no.
First, I consulted with Keith on doing these measurements, have designed an Uuber Sub with a 9Hz corner and full range theater speakers for him and I had designed the contrabass he tested once so there is potentially some contamination haha.

Yes, I know. That's partly why I quoted him. I've followed your career for a long while. The tapped horn stuff is an outstanding addition to a long list of accomplishments. My hat's off.

A few thoughts,
If one had ten different subwoofers with identical response shapes and cabinet sizes and you measured them in half space and ranked them according to maximum output, you would find that the strongest one out doors was also the strongest one indoors and so on.
The room doesn’t effect which one is the most powerful.
If you took ten subs which all had different low corners, the one with the lowest cutoff out doors will also have the lowest cutoff indoors.

Your points are taken, but it's the signal chain and the roll off profile of the sub that determines the lowest cutoff in most rooms.

If I place a ported or tapped horn sub in my room with a 6th order roll off at 20Hz (HP protected), but my sealed sub has a 2nd order roll off at 20Hz, the sealed sub will have the lowest corner in-room by 2 octaves.

The requirement for maximum output then would be determined by my choices of source material and listening levels, and met by multiples.

If you took one subwoofer and placed it in a room, you would find the response has significantly changed and is different everywhere you measure. If you took that same subwoofer and measured it in a different room, you would find another set of different response curves.

If you had used a fixed drive level and measured the radiator motion or internal pressure during all these room tests, you would find the room has essentially no impact on the actual operation of the woofer, in reality the room effects what happens between the speaker output and microphone.
Since when you measure outside, you see only what the speaker is doing, it provides more information than measuring inside where even a small change in position, subwoofer shape or configuration can produce wildly different measurements.

I guess the way I see it is that everyone’s room will greatly alter what reaches the microphone, even in that same room, changing the location of the mic or speaker will alter that too.
What everyone’s rooms will do is different.
That has no bearing on what an optimized subwoofer design looks like measured in half space, does not ‘invert” any thing so far as desirability, distortion, cutoff etc..
What you can get in a room is a matter of placement, speaker capacity and EQ, that is to say making the best of what your individual room (and speaker /listener location)does..

Yes. I'm not trying to confuse a rooms influence on the (+/-) results of the frequency response with the fact that the point at which that room can no longer support standing waves is very predictable and can be used to improve performance of the sub in that room. IF that sub has the flexibility to conform its response to that transfer function profile.

Below the modal region microphone placement is largely irrelevant.

As you can see in this experiment; The sub is placed. The mic is placed 1M from the sub and measured. The mic is then moved to 4M from the sub and measured.

The FR changes in the modal region, due to the mic placement difference regarding the rooms modes. The influence of the inverse square law is also evident in the general drop in SPL of 12dB for doubling the distance twice.

But, below the modal region, FR is largely unaffected, and the inverse square law no longer applies.

http://i469.photobucket.com/albums/rr55/Bosobass/inroom.jpg

Regarding the significance of outdoor measurements to any given room, here is an example I like to use. This is Ilkka's outdoor test of an Adire Tumult MKI in approximately 3.5 cubes, driven by a 1200W (rated) amp.

I took the graph and overlaid a curve that represents the maximum output curve, limited by 10% THD.

I then overlaid a curve that represents Ilkka's results for the sub using the CEA 2010 standard for maximum output vs non linear distortions.

Lastly, I overlaid Tom Nousaine's 10% THD limited max output curve from when he tested the same driver in the same box, driven also by a 1200W (rated) amp, but done indoors in a 7500 cubes room at 2M.

http://i469.photobucket.com/albums/rr55/Bosobass/MeasurementsTumultMKI.jpg

Firstly evident is the bump at 32Hz that's reflected in all of Nousaine's sub test results, no doubt a room influence anomaly, and I've always marveled at how no one ever caught that glaring fact.

My point is that there is a great deal of difference in these results. Depending on them for anything of substance from a buyer's standpoint... well, it's just beyond me.

There was a guy tearing up on Brian's servo 12" very small sealed sub, based solely upon Ilkka's THD sweeps. The sub package is easily one of the best sub values in the world and sounds great when used within its designed parameters, yet some wank was going off after seeing the test results.

All that being said, bass Horn systems, being an acoustic coupler DO feel the room to a varying degree and appear to drive the additive modes somewhat less strongly.
Best,
Tom Danley

This is the part that is most interesting about the tapped horn in a room. Could you be more specific? Have you seen different results, using the DTS-20 for example, with the mouth at different positions, by placing the sub upright vs on edge, etc.?

Bosso