lets bring back sub testing - Page 7 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #181 of 479 Old 02-10-2011, 02:24 PM
AVS Special Member
 
jpmst3's Avatar
 
Join Date: Dec 2005
Location: Davidsville, PA
Posts: 8,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 186
^^^^^^^^

+1

jpmst3 is offline  
Sponsored Links
Advertisement
 
post #182 of 479 Old 02-10-2011, 08:00 PM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,079
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 184
Sounds good. I think it would be best to use the same driver in all of the alignments and eq all of them to the same basic fr shape or close. Then we could see what enclosure effects are on the performance if the sub is asked to reproduce the same signal in the same manner. An article it will be. ( Soho... Flh? You just keep trying to squeeze that in on me don't you?)
Ricci is offline  
post #183 of 479 Old 02-10-2011, 08:07 PM
AVS Special Member
 
jpmst3's Avatar
 
Join Date: Dec 2005
Location: Davidsville, PA
Posts: 8,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 186
Quote:
Originally Posted by Ricci View Post

Sounds good. I think it would be best to use the same driver in all of the alignments and eq all of them to the same basic fr shape or close. Then we could see what enclosure effects are on the performance if the sub is asked to reproduce the same signal in the same manner.

That will be so sweet! Talk about food for thought and debate!

jpmst3 is offline  
post #184 of 479 Old 02-11-2011, 06:30 AM
AVS Addicted Member
 
penngray's Avatar
 
Join Date: Feb 2006
Location: Florida
Posts: 26,779
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 29
Quote:
Originally Posted by Ricci View Post

Sounds good. I think it would be best to use the same driver in all of the alignments and eq all of them to the same basic fr shape or close. Then we could see what enclosure effects are on the performance if the sub is asked to reproduce the same signal in the same manner. An article it will be. ( Soho... Flh? You just keep trying to squeeze that in on me don't you?)

Now that would be a great test!!

It is not "open-minded" to reject knowledge - Bob Lee
penngray is offline  
post #185 of 479 Old 02-11-2011, 06:32 AM
AVS Addicted Member
 
penngray's Avatar
 
Join Date: Feb 2006
Location: Florida
Posts: 26,779
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 29
Quote:
Originally Posted by Ricci View Post

I would definitely not use some big, heavy, unwieldy and pretty brute like that. That thing is upstairs at my house. Not fun. I'd use a small sealed 12 or 15" for that.

$900 is a rough DIY estimate to buy the drivers and build an approximate enclosure. Good luck making it as well as Nathan, getting a nice veneer finish, or executing it as well. The real version costs quite a bit more than that. BTW still for sale! Someone offer me $600!

Um...sorry but what is $600??

It is not "open-minded" to reject knowledge - Bob Lee
penngray is offline  
post #186 of 479 Old 02-11-2011, 09:39 AM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,079
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 184
The Funkywaves FW 15.2. 2 Css sdx 15's in the cab which is a cylindrical enclosure housing dual 4 cu ft sealed enclosures and finished in a very nice lacewood veneer.
Ricci is offline  
post #187 of 479 Old 02-11-2011, 12:14 PM
Advanced Member
 
MBentz's Avatar
 
Join Date: Jun 2006
Location: Chicago
Posts: 930
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 36
Quote:
Originally Posted by Ricci View Post
Thanks.

Btw, you might find this article interesting (see pages 12-19):
ftp://ftp.ni.com/pub/devzone/pdf/tut_4278.pdf

Or here's a web-based link:
http://zone.ni.com/devzone/cda/tut/p/id/4278

Tables 1 and 3 are the ones of interest.

You might want to stick to Hann or Blackman since the worst case amplitude error is about 1dB and their side lobes roll off faster than the natural acoustic rolloff of the units being tested. A classic issue would be a high Q box tuning resulting in a fast acoustic roll-off, but a window with a slow slope will make it look like it is rolling off slower.

Another way around this is to play a steady state tone and then take a fixed amplitude measurement, but then that requires the environment noise to be quiet. I know this is how the guys at Klipsch do it though. It might be worthwhile to just experiment with a few very different subwoofer alignments to get a feel for the window that most accurately matches the steady state frequency amplitude measurement.

Btw, I think what you're doing is awesome and I'm glad to see measurements like this taking place. I just thought I'd provide some suggestions regarding window artifacts since I'm sure this data will become a reference for years to come.

Also, the width of the main lobe can be narrowed by increasing your window length...there's no reason not to extend your sweep and expand your window out to the limit of your first reflection.

-Mike Bentz
~It's all about compromise~
MBentz is offline  
post #188 of 479 Old 02-12-2011, 10:36 AM
AVS Special Member
 
Warpdrv's Avatar
 
Join Date: Oct 2005
Location: Wisconsin
Posts: 7,350
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 15
Ricci, does it make any sense to run at least 1 or 2 THD sweeps at a more normal listening level to kinda keep things in check.

We were comparing the DTS vs LMS and were curious roughly when the THD starts to ramp up.

Question that was asked - Which I thought was a good question by Jostenmeat -

We can all sense differences in output, and can hear differences in decay/overhang, but what distortion levels/percentages are discernible to us with LFE frequencies, and just how far beyond these thresholds do horns get to? I mean I read up on the Fitzmaurice folded horn, and sub-5% distortion . . . is that even perceivable with LFE (honest question)?
Warpdrv is offline  
post #189 of 479 Old 02-12-2011, 11:07 AM
AVS Special Member
 
maxmercy's Avatar
 
Join Date: Nov 2008
Posts: 2,305
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
You will hear different answers....but at 20Hz, I can hear the difference between 5% and 10%, and below 3%, I can't tell anything.

Quoted from Monte Kay's page:

http://www.mfk-projects.com/theatre_woofer.htm


While it is widely accepted in the industry that non linear distortion at low frequency is not particularly audible I am convinced that it is audible. In fact I believe that non linear distortion is the most audible at low frequency. One look at the equal loudness curves of human hearing should convince anyone that non linear distortion is least audible above about 3 KHz and most audible below 3 KHz. Above about 10 KHz it should be completely inaudible because the 2nd harmonic is exceeding the human hearing range. At 20 Hz the human ear will hear an equal level 40 Hz tone as 20 dB louder based on a 90 dB reference level. This means the 40 Hz harmonic must be 20 dB below the 20 Hz fundamental just to sound as if it is the same level or 100% 2nd harmonic distortion.

It's very difficult to achieve low distortion at frequencies in the 20 Hz range. Consequently I wonder how test were conducted to produce the widely held belief that distortion is inaudible at low frequency? Since most woofers produce at least 10% distortion at 20 Hz which sounds like 100% distortion at the 2nd and far higher at the 3rd, they have no clean reference to determine if induced distortion is audible. The test platform is starting with too much distortion to begin with for anyone to assess that an induced distortion is or is not audible.


Until you have a clean reference, you cannot tell.....

JSS
maxmercy is offline  
post #190 of 479 Old 02-12-2011, 12:57 PM
AVS Addicted Member
 
noah katz's Avatar
 
Join Date: Apr 1999
Location: Mountain View, CA USA
Posts: 20,346
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 133
I wonder if the search for such low bass distortion is a bit Quixotic.

The reasoning about effective distortion based on the hearing curves is sound, but it assumes that very low amounts of distortion are in fact audible.

I wonder what the definition of "audible" is.

Does it mean that it's distinguishable from a lower distortion reference, or that it sounds subjectively less clean or outright distorted?

Noah
noah katz is online now  
post #191 of 479 Old 02-12-2011, 01:31 PM
AVS Special Member
 
Join Date: Mar 2003
Posts: 4,509
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked: 606
Quote:
Originally Posted by Warpdrv View Post

Ricci, does it make any sense to run at least 1 or 2 THD sweeps at a more normal listening level to kinda keep things in check.

We were comparing the DTS vs LMS and were curious roughly when the THD starts to ramp up.

Question that was asked - Which I thought was a good question by Jostenmeat -

We can all sense differences in output, and can hear differences in decay/overhang, but what distortion levels/percentages are discernible to us with LFE frequencies, and just how far beyond these thresholds do horns get to? I mean I read up on the Fitzmaurice folded horn, and sub-5% distortion . . . is that even perceivable with LFE (honest question)?

It appears that no one has looked at Josh's DTS-10 results, which seem to coincide fairly closely to my much attacked posts in the DTS thread.



Of the many condescending comments I was pelted with:

Quote:
Originally Posted by noah katz View Post

bosso,

"OK, I hafta say, I'm disappointed."

By now it's clear that you very much want to be.

You've implied/said more than once that because the DTS-10 is performing worse in Ricci's room than outdoors that it must be lacking.

You know *way* better than this and I'm sorry to say that I'm disappointed after having gained a lot of respect for you for your usually informed and rational posts.

Granted, it seems that we expected too much, however you're putting a lot of spin on what was initially said.

For example, I said no amount of Mael's in the same size box, and I stand by that.

If you disagree, please provide a simulation that shows otherwise, as you've done many times before.

"Noah says it's your room and that I should know better."

As Dennis pointed out, you still haven't dug yourself out of that hole w/a rational response, just bluster.

I have to say, your bluster is very good; have you considered politics?

Great stuff. Rather than post a simulation and debate this sort of posturing on the side of delusion over reality, I patiently awaited Josh's results, as I was all but certain what they would reveal, after seeing Heddon's botched GP results and Josh's in-room compression sweeps (compared with his XXX in-room compression sweeps).

Never was sure what Noah was referring to when he said I should know better that to post what I did, but the truth is that Josh had provided enough data from his in-room sweeps and THD numbers to correlate well enough with the Heddon numbers to draw conclusions that were at the very least much closer to reality than Tom Danley's suggestion:

Quote:


Tell me why you didn't post a long rebuttal to Noah's earlier comment:

I don't check in here every day, I have stuff to do you know and can't read every post .Besides what he said was essentially what I had said more or less.
According to my computer model, it should be able to produce over 120dB at 1m at 12Hz before Xmax is reached. Also I said that reality is always less but has yet to be measured.

Instead of being Don Quixote based on rather scant data, why not wait until the CEA measurements are done?. Now I am curious, what the subwoofers are you talking about and how do they perform RE: Illka's test?

Well, he was only off by 20dB.

Since you can easily put 4-MX-18s in a DTS box, we'll have to ask Noah if he still "stands by his statement" that no amount of Maels in the DTS box will approach the performance, but, Josh has measured the XXX and a pair of SDX-15s in sealed boxes, and Ilk, of course, has measured the LMS-18 in a smallish box.

Here is the 110dB sweep of the DTS-10 laid over the sweeps of the LMS with compression shown for the DTS and the LMS @ 115dB. I also placed a trace that would conservatively represent one of Warp's 2xLMS subs:



I then overlaid the single LMS THD results from its 115dB sweep for comparison:



Conclusion? A pair of LMS 18s, or a pair of XXXs, or 4 SDXs will outperform the DTS-10. 8-Ed 18s with 10KW, as I said then and shouldn't have to repeat here, will outperform a pair of DTS-10s in every category.

You can easily debate <20 Hz harmonic distortion because it will be considerably reduced by typical room gain, but I'm sure no one here can easily explain away the DTS-10s >20 Hz THD as being inaudible.

Based on these results, one would have to conclude that harmonic distortion is preferable and subjectively is described as "that extremely clean horn sound".

IMO, the DTS-10 is a one octave bandpass subwoofer. It's good from 12-25 Hz. Elsewhere, not so good, unless I've been misreading test results for 8 years.

Bosso
bossobass is offline  
post #192 of 479 Old 02-12-2011, 02:08 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,176
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 129 Post(s)
Liked: 631
Very informative, Bosso. Fantastic read.

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is online now  
post #193 of 479 Old 02-12-2011, 02:33 PM
AVS Special Member
 
jpmst3's Avatar
 
Join Date: Dec 2005
Location: Davidsville, PA
Posts: 8,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 186
Very interesting!

jpmst3 is offline  
post #194 of 479 Old 02-12-2011, 02:41 PM
AVS Special Member
 
maxmercy's Avatar
 
Join Date: Nov 2008
Posts: 2,305
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
Bosso has simply pointed out facts. No replacement for linear displacement down low........these facts are often unpopular, and Bosso has felt the sting more than once.....

You can 'trick' an enclosure to give you more displacement than the cone area and linear excursion available, but you must give up something.........usually bandwidth and space occupied, but you will give up something......

By the same token, linear displacement in a small space/volume can get expensive....

Again, pick where you want to get off the train.......

JSS
maxmercy is offline  
post #195 of 479 Old 02-12-2011, 03:06 PM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,079
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 184
One caveat Bosso. Please use my data to compare against the dts10. I also did an lms test and while I was admittedly slightly conservative with it, not wanting to damage the drivers top assembly, not being produced in that configuration anymore, at least it was done on the same day with the same equipment. My test site is a little noisy so lower volume 90 db thd sweeps are going to be a little higher than in reality. Actually the dts10 thd would not be that bad if the resonances imposed by the cabinet loading weren't severely boosting the harmonics at some frequencies. Looks like that will be part of the tapped horn alignment.
Ricci is offline  
post #196 of 479 Old 02-12-2011, 11:37 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,898
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked: 831
i'm having a hard time matching up ricci's measurements with bosso's post. are you using data-bass.com measurements, or something else? the danley spec sheet shows much higher spl. are we saying that the danley spec sheet is baloney?

"A pair of LMS 18s...will outperform a pair of DTS-10s in every category."

first, isn't the dts-10 far more efficient? if so, spl per watt goes to dts-10.

second, a pair of dts-10s will provide another 6db, which would put it above dual lms's in the graph provided.

maybe it would be a good idea to cite your sources, so we can follow along.

 

DTS%2010%20spec%20sheet.pdf 95.4267578125k . file

Listen. It's All Good.
LTD02 is online now  
post #197 of 479 Old 02-13-2011, 12:00 AM
AVS Special Member
 
NEO Dan's Avatar
 
Join Date: Jul 2006
Location: North East Ohio
Posts: 2,978
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
You've attached the wrong file fella

Regards,
Dan
NEO Dan is offline  
post #198 of 479 Old 02-13-2011, 12:37 AM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,898
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked: 831
"You've attached the wrong file fella"

thanks. changed. i had both on my desktop. since spaces are translated as %20, both filenames look almost identical.

Listen. It's All Good.
LTD02 is online now  
post #199 of 479 Old 02-13-2011, 07:10 AM
Member
 
fnt62's Avatar
 
Join Date: Feb 2011
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by bossobass View Post

It appears that no one has looked at Josh's DTS-10 results, which seem to coincide fairly closely to my much attacked posts in the DTS thread.



Of the many condescending comments I was pelted with:



Great stuff. Rather than post a simulation and debate this sort of posturing on the side of delusion over reality, I patiently awaited Josh's results, as I was all but certain what they would reveal, after seeing Heddon's botched GP results and Josh's in-room compression sweeps (compared with his XXX in-room compression sweeps).

Never was sure what Noah was referring to when he said I should know better that to post what I did, but the truth is that Josh had provided enough data from his in-room sweeps and THD numbers to correlate well enough with the Heddon numbers to draw conclusions that were at the very least much closer to reality than Tom Danley's suggestion:



Well, he was only off by 20dB.

Since you can easily put 4-MX-18s in a DTS box, we'll have to ask Noah if he still "stands by his statement" that no amount of Maels in the DTS box will approach the performance, but, Josh has measured the XXX and a pair of SDX-15s in sealed boxes, and Ilk, of course, has measured the LMS-18 in a smallish box.

Here is the 110dB sweep of the DTS-10 laid over the sweeps of the LMS with compression shown for the DTS and the LMS @ 115dB. I also placed a trace that would conservatively represent one of Warp's 2xLMS subs:



I then overlaid the single LMS THD results from its 115dB sweep for comparison:



Conclusion? A pair of LMS 18s, or a pair of XXXs, or 4 SDXs will outperform the DTS-10. 8-Ed 18s with 10KW, as I said then and shouldn't have to repeat here, will outperform a pair of DTS-10s in every category.

You can easily debate <20 Hz harmonic distortion because it will be considerably reduced by typical room gain, but I'm sure no one here can easily explain away the DTS-10s >20 Hz THD as being inaudible.

Based on these results, one would have to conclude that harmonic distortion is preferable and subjectively is described as "that extremely clean horn sound".

IMO, the DTS-10 is a one octave bandpass subwoofer. It's good from 12-25 Hz. Elsewhere, not so good, unless I've been misreading test results for 8 years.

Bosso

You're not the only one who's been patiently waiting for actual test results on the "highly acclaimed" tapped horn designs. The distortion plot Ricci posted is one of the ugliest I've ever seen. What I still can't understand though is why it's taken so long and so many builds for this information to come out. I'm not saying you have to be in the fruitloop "extremely clean horn sound" camp to like them. If you're after a lot of decibels for a few watts - I guess they have some advantages. But why can't people be real about how clean they are when they do in fact sound boomy and the raw data backs that up?
fnt62 is offline  
post #200 of 479 Old 02-13-2011, 07:51 AM
AVS Special Member
 
tony123's Avatar
 
Join Date: Jul 2002
Location: Upstate, South Carolina
Posts: 4,992
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 25
I wonder how much of an impact these numbers have to my ears? I don't have the experience of some of you guys, but I've been in the hobby for 30 years now, and have owned or heard several dozen subs of about every type. I'm not hearing "ugly, distorted, boomy and bloated bass" from my Tapped horns compared to any other subs I've heard. Those last charts would have you believe it was absolute crap...I'm just not hearing that.

The "Twinseltown" Theater
Construction Thread
tony123 is offline  
post #201 of 479 Old 02-13-2011, 08:47 AM
AVS Special Member
 
Join Date: Mar 2003
Posts: 4,509
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked: 606
Quote:
Originally Posted by Ricci View Post

One caveat Bosso. Please use my data to compare against the dts10. I also did an lms test and while I was admittedly slightly conservative with it, not wanting to damage the drivers top assembly, not being produced in that configuration anymore, at least it was done on the same day with the same equipment. My test site is a little noisy so lower volume 90 db thd sweeps are going to be a little higher than in reality. Actually the dts10 thd would not be that bad if the resonances imposed by the cabinet loading weren't severely boosting the harmonics at some frequencies. Looks like that will be part of the tapped horn alignment.

I thought you might add the caveat, you slave driver.

Smooth your results. Those squiggles make for a LOT of work to create these graph comparisons. I admit I was lazy and just used the Ilk LMS stuff I already had in my files.

Here are the comparisons with your LMS results:





Although the THD results are slightly different, your output traces are also slightly different, partially because of the larger box, partially because of a different amp and partially because you show higher output.

That's why I said the guesstimate of one of Warp's subs was 'conservative' in the first post. I also am sure that a dual opposed version would show a bit less THD, or at least a different curve (trend).

But, the differences are negligible in that they don't put a dent in the difference vs the DTS-10.

Bosso
bossobass is offline  
post #202 of 479 Old 02-13-2011, 08:47 AM
AVS Special Member
 
jpmst3's Avatar
 
Join Date: Dec 2005
Location: Davidsville, PA
Posts: 8,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 186
I am curious to see if Ivan can chime in with some other data to add to the discussion.

jpmst3 is offline  
post #203 of 479 Old 02-13-2011, 08:58 AM
AVS Special Member
 
Join Date: Mar 2003
Posts: 4,509
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked: 606
Quote:
Originally Posted by LTD02 View Post
i'm having a hard time matching up ricci's measurements with bosso's post. are you using data-bass.com measurements, or something else? the danley spec sheet shows much higher spl. are we saying that the danley spec sheet is baloney?

"A pair of LMS 18s...will outperform a pair of DTS-10s in every category."

first, isn't the dts-10 far more efficient? if so, spl per watt goes to dts-10.

second, a pair of dts-10s will provide another 6db, which would put it above dual lms's in the graph provided.

maybe it would be a good idea to cite your sources, so we can follow along.

This is typical of the ether most TH fans have seemed to be under. you really have to spend a percentage of the time you put into glorifying an alignment reading what I post vs the usual 'skim and bash' approach. I said:

Quote:
Conclusion? A pair of LMS 18s, or a pair of XXXs, or 4 SDXs will outperform the DTS-10. 8-Ed 18s with 10KW, as I said then and shouldn't have to repeat here, will outperform a pair of DTS-10s in every category.
Bosso
bossobass is offline  
post #204 of 479 Old 02-13-2011, 09:57 AM
AVS Special Member
 
Join Date: Mar 2003
Posts: 4,509
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked: 606
Quote:
Originally Posted by tony123 View Post
I wonder how much of an impact these numbers have to my ears? I don't have the experience of some of you guys, but I've been in the hobby for 30 years now, and have owned or heard several dozen subs of about every type. I'm not hearing "ugly, distorted, boomy and bloated bass" from my Tapped horns compared to any other subs I've heard. Those last charts would have you believe it was absolute crap...I'm just not hearing that.
I've never said (or believed) that these THD and sine sweep graphs mean a whole lot aside from how a subwoofer will handle being water boarded, which does have some value when comparing subwoofers that have been tested by these methods.

IMO, there is absolutely nothing wrong with saying "It sounds different, and I like the difference".

I once, back when, had a pair of 15s from China that had a suspension so stiff you could prit'-near stand on the cone and barely move them. They had, of course, monstrously powerful motors.

This basically meant that they were all suspension and no air spring. Unfortunately, there were no proprietary suspension parts or design and, as a result, the sub gave off quite high 2HD.

I decided to hold a listening session using this high 2HD sub vs some state of the art sealed subs with a young group of musicians and was very surprised at how many of them preferred the higher 2HD sub, generally referring to it as 'tighter' and/or 'cleaner'. I've never had a problem with personal preferences in music or EQ of the reproduction of that music, per se. It was an interesting discovery and nothing more. After all, most musicians today distort the heck out of their instruments to arrive at a sound they personally prefer, whether it be drums, guitar, bass, keys, horns, violins or even their voices.

That is as opposed to those who have said things akin to "it's cleaner and louder and more efficient and can leap tall buildings with a single bound and you are only disagreeing with those 'facts' because you have an agenda", which is nothing more than a delusional BS rant.

Bosso
bossobass is offline  
post #205 of 479 Old 02-13-2011, 10:58 AM
AVS Special Member
 
soho54's Avatar
 
Join Date: Sep 2005
Posts: 3,329
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Quote:
Originally Posted by LTD02 View Post

the danley spec sheet shows much higher spl. are we saying that the danley spec sheet is baloney?

The DSL specs are what they are. Danley has said himself that they have to do what everyone else does. They claim to not do it as much, but they have to do it.

The obvious things to start looking at is that there are no 1w/1m measurements given. DSL uses 2.83v as the sensitivity yard stick, no matter the subs impedance. Notice the Impedance graph here, it was ~2ohm as tested, so 2.83v is a bit more than the 1.41v a 2ohm load needs for 1w.

They sometimes put 100w/10m on the graphs, but it is still in reference to 1w/1m where 1/w is always 2.83v. It has been said that that wasn't the case by someone, can't remember who, but it was not the person doing the testing. Tom said he would have them change it, but it was never changed. All numbers work using 2.83v, and 28v. Not actually watts.

There is the way TEF is normally used, which means the graph is naturally smoothed off as things get lower in frequency. Seems like the fast sweep is limited to 2Hz resolution, or 1/10 at 20Hz. There is nothing wrong with this, but one needs to be aware of it when trying to make comparisons. DSL is prety good about using as low a resolution as possible. It says 2Hz here for example.

Finally from TD himself, "Also, in pro sound, it IS customary to measure power etc using pink noise." Emphasis not mine.

"Max SPL is an imaginary figure in pro sound, NO ONE I have heard of actually measures this number or if they do, does it in a meaningful way (you might recall discussion on PSW). " Emphasis not mine.

"Generally that “peak” figure is found by taking the sensitivity and power rating to calculate the max theoretical continuous output and then adding the 6dB peaks above the average level and then in some cases, add an additional 3 dB to that to account for “program power” and some add even more. This mathematical slight of hand is how a floor monitor can have a rated peak SPL of 148dB even though it has a 15 and 2 inch comp driver.

Our “max SPL” figure for our subwoofer is also imaginary but the idea of doing it the traditional way made some ill, we took the sensitivity and rated power and then added 3 dB not 6 dB. That figure is more consistent with what can measure with music and a peak hold SLM.
"

"Nobody I know rates subwoofers based on a 0dB sine wave and “program” is normally defined as +3dB over the continuous (sine equivalent) rating anyway. "

As Tom always says, real measurements are what counts.
soho54 is offline  
post #206 of 479 Old 02-13-2011, 12:08 PM
AVS Special Member
 
soho54's Avatar
 
Join Date: Sep 2005
Posts: 3,329
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Quote:
Originally Posted by tony123 View Post

I wonder how much of an impact these numbers have to my ears? I don't have the experience of some of you guys, but I've been in the hobby for 30 years now, and have owned or heard several dozen subs of about every type. I'm not hearing "ugly, distorted, boomy and bloated bass" from my Tapped horns compared to any other subs I've heard. Those last charts would have you believe it was absolute crap...I'm just not hearing that.

THD charts do not equate to listener perceived sound quality really, just deviation from input signal.

The THD charts are exactly what one should expect from the FR graphs. It is the reason DSL used the 1/4wave resonators in the DTS-20, and the reason I am not a fan of smaller THs. It isn't just a TH thing though, a FLH will do the same thing.

The talk of horns having lower distortions is more than just THD, there are other waveform distortions, but even with THD it is only true when in comparison the the same number of the same driver in another alignment at the same SPL.

Ricci, could you run the pair of DSL or LMSR drivers in a sealed, and ported enclosure in a future test? This would help any explanations.

Of course, the DTS-10 is very small for its cutoff, it might be a close call here.
soho54 is offline  
post #207 of 479 Old 02-13-2011, 12:08 PM
Member
 
fnt62's Avatar
 
Join Date: Feb 2011
Posts: 18
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by soho54 View Post


As Tom always says, real measurements are what counts.

Thank god for Tom and real measurements.
fnt62 is offline  
post #208 of 479 Old 02-13-2011, 02:59 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,898
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked: 831
soho, with the basic frequency sweep in the dts-10 spec sheet, it shows a little over 100db sensitivity at 2.83v into 2.6 min ohms (which is a little over 3 watts), but that still doesn't explain the high reported sensitivities of the danley horns (even at 3 watts, ricci's measurement would be around 95db, which seems about right in hornresp). are you suggesting that they use pink noise instead of a sine wave for the frequency sweep, which would give even higher sensitivity (of ~5db or so)? is that the "danley magic" in horn design...creative measurements?

bosso, i wasn't glorifying any alignment, nor was i "skimming and bashing". i was trying to reconcile your claims, danley spec sheet claims, and ricci's measurements. the dts-10 appears to do 112db at 20hz (data-bass.com, dts-10, large signal measurement page). adding a second dts-10 and power will give ~118db at 20hz. how is the dual lms setup outperforming the dual dts-10 setup when the lms setup has less spl?

Listen. It's All Good.
LTD02 is online now  
post #209 of 479 Old 02-13-2011, 03:08 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,898
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked: 831
there is also another anomaly. what is called the "115db" measurement on the lms produces 115db at the high end of the operating range. what is called "115db" measurement on the dts-10 produces 125db at the high end of the operating range.

maybe the high distortion in the dts-10 sweep is actually coming from the amplifier and not from the sub?

Listen. It's All Good.
LTD02 is online now  
post #210 of 479 Old 02-13-2011, 03:15 PM
AVS Special Member
 
tony123's Avatar
 
Join Date: Jul 2002
Location: Upstate, South Carolina
Posts: 4,992
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 25
boss and soho, thanks for the response and insight.

The "Twinseltown" Theater
Construction Thread
tony123 is offline  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off