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post #31 of 215 Old 11-10-2010, 03:58 PM
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Originally Posted by pboy207 View Post

Penn or any anyone for that matter,

I've seen it mention several times about meaningful spl at 10hz. What would be enough spl at 10hz to be meangingful? Also when manufactures say flat to a certain frequency, what spl is this based on? If someone can explain this or point me to where this is explained. It would be appreciated. Thanks

Actually, meaningful output at any frequency in the LFE bandwidth is a simple matter to conclude. You simply have to have the ability to playback what's on the disc, which has absolutely nothing to do with the equal loudness curves, house curves, auditory masking studies or any of the other unrelated stuff people always throw into the discussion to confuse the issue.

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post #32 of 215 Old 11-10-2010, 04:04 PM
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Originally Posted by desertdome View Post

The 11dB difference is maximum output at a given frequency. The +/-2dB is when sent a frequency sweep at a lower output level.

I appreciate the post, but I understand the difference.

It's my opinion that the max output numbers should form a curve that resembles the claimed native frequency response magnitude. When there is a large disparity between the two, the claimed native response ceases to have much meaning.

I can dial in a ruler flat response to 9Hz with the Bassis, but then throw the max output numbers out the window, because the amp will run out of gas far before the max output at 63Hz can be used.

If I employ limiters to prevent that from happening, the max output curve no longer even closely resembles the published FR curve, as in the Velo DD-18:



Max clean output, in the context of FR, resides at the subs weakest point, not its strongest point. A distinction should be made, especially when a huge disparity between the two exists, or max output at 'x' frequency specs should not be included.

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post #33 of 215 Old 11-10-2010, 06:53 PM
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Originally Posted by bossobass View Post
Any examples of such an amp?
Dunno.

OK, so I agree with all of your points

Wait a sec, didn't the NAD Power Envelope designs have 6 dB dynamic capability (though I don't think they did it the way I described), and for that matter wasn't there a period when mfgr's were touting dynamic power?

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post #34 of 215 Old 11-11-2010, 04:35 AM
 
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Quote:
Originally Posted by bossobass View Post

I appreciate the post, but I understand the difference.

It's my opinion that the max output numbers should form a curve that resembles the claimed native frequency response magnitude. When there is a large disparity between the two, the claimed native response ceases to have much meaning.

I can dial in a ruler flat response to 9Hz with the Bassis, but then throw the max output numbers out the window, because the amp will run out of gas far before the max output at 63Hz can be used.

If I employ limiters to prevent that from happening, the max output curve no longer even closely resembles the published FR curve, as in the Velo DD-18:



Max clean output, in the context of FR, resides at the subs weakest point, not its strongest point. A distinction should be made, especially when a huge disparity between the two exists, or max output at 'x' frequency specs should not be included.

Bosso

About a 25db difference between having the response flat vs the peaked response. Huge difference.
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post #35 of 215 Old 11-11-2010, 04:43 AM
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Glad to see it's being discussed here as I'm somewhat miffed by the numbers as well. With a 350 watt amp those numbers are astonishing unless the driver is close to 100 on the efficiency scale (though I seem to recall a discussion somewhere that there are trade off's in design with efficiency and something else when it came to drivers). At $900 with that fit and finish and box size, if they truly accomplished the feat (i.e., those numbers) it would definitely take a run for the money on DIY if you factor in anything at all for labour/time.

As for the ULS, FWIW someone posted measurements in this review ...

http://www.audaud.com/article.php?ArticleID=8067

 

My DIY Subs ... http://www.avsforum.com/avs-vb/showthread.php?t=1233892

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J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #36 of 215 Old 11-11-2010, 05:44 AM
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So who is going to raise this issue over on the owner's thread??

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post #37 of 215 Old 11-11-2010, 06:14 AM
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No use in ragging on the parade. Even if the sub can do within 3 to 5 db of what they are claiming it's still a great offering for a commercial subwoofer at $900. Someone needs to grab the driver and measure the T/S specs!

 

My DIY Subs ... http://www.avsforum.com/avs-vb/showthread.php?t=1233892

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post #38 of 215 Old 11-11-2010, 06:16 AM
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Well Im going to ask the simple question

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post #39 of 215 Old 11-11-2010, 06:18 AM
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I'm just glad Pete somewhat agreed their "room claims" need to be adjusted. I still crack up every time I see the "Loudness Level - 4 - HUGE Rooms" rating for the sealed ULS-15.

Though their solution was to remove the room rating for the VTF-15H and keep it for the rest!

I'll tell you one thing, SVS is going to have a heck of a time with the ID crowd with these kinds of offerings at those price points. Mind you, sounds like they are pushing more towards a hybrid dealer model now anyhow.

 

My DIY Subs ... http://www.avsforum.com/avs-vb/showthread.php?t=1233892

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post #40 of 215 Old 11-11-2010, 11:28 AM
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Quote:
Originally Posted by bossobass View Post

Soon we'll be seeing under specifications:

Max output: Teeth rattling, pants flapping.
Extension: Really, really, really deep.
Plate amp: 20,000W peak (150W RMS).

Bosso

The Powersoft DIGAM K series aren't too far off this type of amplifier. Check the K10 & K20.

Mark Seaton
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post #41 of 215 Old 11-11-2010, 11:50 AM
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Quote:
Originally Posted by Ricci View Post

Right. If you add up all of the hd allowed by cea2010, thd of almost 40% is allowable. For all intensive purposes its max peak burst output before the sub descends into total distortion and overload.

Im with Bosso on this one. It will take one special 15" to hit those output #'s in a 1m gp test. Those seem like in room #s to me. 5 cu ft and 1 15" with 1400 w peak can only do so much. You'd have to expect some compression from the driver and ports both. Either way it'd take one seriously efficient 15".

A quick model I did of an approximation of what I would guess is close to their 15" driver in a box approximately that size tuned to 22Hz with 1400W correlates pretty well with the CEA peak output numbers listed. I doubt that output could be sustained for more than a few seconds, but it is certainly within the realm of possibility. It also looks as though the 19-35Hz range will take a noticeable hit in the same output measurements when the 16Hz (one port plugged) mode is engaged. The triangular ports are an interesting choice. The flaring on the outlet side looks like ~3/4" radius which seems a bit conservative, so it should be interesting to see what is observed in terms of port airflow noise at those higher levels. The triangle profile holds both benefits and detriments as compared to a round or rectangular ports, so the observations from users will be interesting to see. This is again a case where measurements really need associated tester observations to insure the testing doesn't overlook relevant details of a differing design.

I don't have an issue with the CEA numbers, but I certainly don't consider them to be all inclusive nor sufficiently detailed to illustrate or differentiate all real use differences between subwoofers.

Mark Seaton
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post #42 of 215 Old 11-11-2010, 05:46 PM
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Quote:
Originally Posted by Mark Seaton View Post

It also looks as though the 19-35Hz range will take a noticeable hit in the same output measurements when the 16Hz (one port plugged) mode is engaged.

Dr. Hsu recently pulled out a random new production unit, and measured max clean peak output with 2 ports open and with 1 port open. At 20Hz, the difference in max clean peak SPL using the CEA2010 stepped harmonic distortion limits was only 0.3dB in favor of 2 ports open mode. At 31.5Hz, the difference is 2.7dB, which is significant but not bad by any means. This subwoofer is very good with 2 ports open or 1 port open.

Quote:


The triangle profile holds both benefits and detriments as compared to a round or rectangular ports, so the observations from users will be interesting to see.

We had the opportunity to compare two prototypes, one with our triangular port design and one with comparably sized round port design with huge flares. Amazingly enough, we found the triangular ports had much less port noise at moderate-to-high playback levels. I won't go into why we think that was the case, but the design ended up to be very effective for us.

Sincerely,

Pete - Hsu Research
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post #43 of 215 Old 11-11-2010, 07:02 PM
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Quote:
Originally Posted by Pete_Hsu View Post

Dr. Hsu recently pulled out a random new production unit, and measured max clean peak output with 2 ports open and with 1 port open. At 20Hz, the difference in max clean peak SPL using the CEA2010 stepped harmonic distortion limits was only 0.3dB in favor of 2 ports open mode. At 31.5Hz, the difference is 2.7dB, which is significant but not bad by any means. This subwoofer is very good with 2 ports open or 1 port open.



We had the opportunity to compare two prototypes, one with our triangular port design and one with comparably sized round port design with huge flares. Amazingly enough, we found the triangular ports had much less port noise at moderate-to-high playback levels. I won't go into why we think that was the case, but the design ended up to be very effective for us.

Sincerely,

Hi Pete,

You know we all love you and the good Doc, but this forum is a bit off the reservation for you.

Since you're here, I wasn't so much questioning the max 6.5 cycle tone burst results at 1M, but more towards how they relate to the posted FR of 15-200Hz (+/-2dB).

First, would you be so kind as to post that measured response and the details?

The only CEA numbers I have to reference are those posted by Ilkka. I've never been a fan of the standard and I don't know of any major manufacturer who uses it.

That said, I'm intrigued by the disparity in the max 1/3 octave single frequency numbers and the posted response. The claimed FR shows a difference between 20Hz and 63Hz of 1dB?, but the CEA max numbers show a difference between 20Hz and 63Hz of 11dB.

Ilk's CEA results of the measured FR vs the CEA numbers for other ported subs, including Hsu subs, at 20Hz and 63Hz are quite closer:

TC2K ported; FR difference = 4dB, CEA difference = 5dB (disparity; 1dB)
SVS PB Ultra; FR difference = 0.5dB, CEA difference = 6dB (disparity; 5.5dB)
PB Ultra 15Hz; FR difference = 2.5dB, CEA difference = 6.2dB (disparity; 3.7dB)
B&K Monolith; FR difference = 6.6dB, CEA difference = 6.6dB (disparity; 0dB)
Hsu VTF-3 MO; FR difference = 8dB, CEA difference = 11dB (disparity; 3dB)
Peerless xls 12"; FR difference = 8dB, CEA difference = 9.7dB (disparity; 1.7dB)
LMS5400+2PR; FR difference = 4.5dB, CEA difference = 4.6dB (disparity; 0.1dB)

Hsu VTF15H; FR difference =1dB?, CEA difference = 11dB (disparity = 10dB)

The disparity looks more like a sealed subwoofer than a ported subwoofer, yet the FR is said to be near ruler flat over more than 3 octaves.

So it looks like a pro sound driver EQ'd to the stated FR, but heavily limited to be able to hit the high notes for test results while exhibiting a rather large departure from its stated FR.

Comments?

Bosso
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post #44 of 215 Old 11-11-2010, 07:35 PM
 
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Quote:
Originally Posted by bossobass View Post

Hi Pete,

You know we all love you and the good Doc, but this forum is a bit off the reservation for you.

Since you're here, I wasn't so much questioning the max 6.5 cycle tone burst results at 1M, but more towards how they relate to the posted FR of 15-200Hz (+/-2dB).

First, would you be so kind as to post that measured response and the details?

The only CEA numbers I have to reference are those posted by Ilkka. I've never been a fan of the standard and I don't know of any major manufacturer who uses it.

That said, I'm intrigued by the disparity in the max 1/3 octave single frequency numbers and the posted response. The claimed FR shows a difference between 20Hz and 63Hz of 1dB?, but the CEA max numbers show a difference between 20Hz and 63Hz of 11dB.

Ilk's CEA results of the measured FR vs the CEA numbers for other ported subs, including Hsu subs, at 20Hz and 63Hz are quite closer:

TC2K ported; FR difference = 4dB, CEA difference = 5dB (disparity; 1dB)
SVS PB Ultra; FR difference = 0.5dB, CEA difference = 6dB (disparity; 5.5dB)
PB Ultra 15Hz; FR difference = 2.5dB, CEA difference = 6.2dB (disparity; 3.7dB)
B&K Monolith; FR difference = 6.6dB, CEA difference = 6.6dB (disparity; 0dB)
Hsu VTF-3 MO; FR difference = 8dB, CEA difference = 11dB (disparity; 3dB)
Peerless xls 12"; FR difference = 8dB, CEA difference = 9.7dB (disparity; 1.7dB)
LMS5400+2PR; FR difference = 4.5dB, CEA difference = 4.6dB (disparity; 0.1dB)

Hsu VTF15H; FR difference =1dB?, CEA difference = 11dB (disparity = 10dB)

The disparity looks more like a sealed subwoofer than a ported subwoofer, yet the FR is said to be near ruler flat over more than 3 octaves.

So it looks like a pro sound driver EQ'd to the stated FR, but heavily limited to be able to hit the high notes for test results while exhibiting a rather large departure from its stated FR.

Comments?

Bosso

Munching on popcorn, waiting for a response.
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post #45 of 215 Old 11-11-2010, 07:36 PM
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Quote:
Originally Posted by Mark Seaton View Post

A quick model I did of an approximation of what I would guess is close to their 15" driver in a box approximately that size tuned to 22Hz with 1400W correlates pretty well with the CEA peak output numbers listed. I doubt that output could be sustained for more than a few seconds, but it is certainly within the realm of possibility. It also looks as though the 19-35Hz range will take a noticeable hit in the same output measurements when the 16Hz (one port plugged) mode is engaged. The triangular ports are an interesting choice. The flaring on the outlet side looks like ~3/4" radius which seems a bit conservative, so it should be interesting to see what is observed in terms of port airflow noise at those higher levels. The triangle profile holds both benefits and detriments as compared to a round or rectangular ports, so the observations from users will be interesting to see. This is again a case where measurements really need associated tester observations to insure the testing doesn't overlook relevant details of a differing design.

I don't have an issue with the CEA numbers, but I certainly don't consider them to be all inclusive nor sufficiently detailed to illustrate or differentiate all real use differences between subwoofers.

Hey I agree Mark its certainly not impossible, but to put it into perspective even an AE TD15X or H, which is pretty durn efficient, much more so than the usual subwoofer driver through the 40-100hz range, in a roughly similar enclosure to the HSU, 5cu ft tuned to 24hz for a guess(about 5cu ft is the max volume that it could realistically be and tuning is probably 22-24hz with both ports open. (even lower tuning drops efficiency up high)) just barely falls short of the quoted numbers with the claimed 1400w (31.5dbw roughly). Sure a few pro drivers will come close to meeting that 123-125db spec but none of them have much more than 10-14mm xmax at most and you'll need more than that for the lower one port blocked tuning or the driver will run out of excursion at the peak above tuning. None of that is taking into account any sort of compression either.

I'm not saying the sub isn't or is a good performer BTW. Hell even if you chop 3 or 4db off of those quoted #'s it'd still be a whole lot of output for the size and money.



On the amplifier front it seems like a lot of amps are built with 3-6db of dynamic power these days (Its marketed as RMS or even continuous power still though) Powersoft, Lab Gruppen, etc... HSU should just join the club and call it a 1400w amp. Most any big multi KW amplifier placed on a 120v 15A or 20a circuit is going to be able to burst its rated power or more momentarily, but the ac line can't provide enough juice to sustain that kind of output so the continuous output is less. Most amps are being designed with short duration burst in mind instead of continuous output these days. They aren't overbuilt enough or meant to do sustained output at clipping so the output is limited to a lower level for longer duration signals, which makes sense really. On the other hand you have 1000w amps that will sit there and do 1000w for 1hr solid like my AE techron's but they are mono, 3 rack spaces and 92lbs each and eat most of a 20A circuit doing that lowly 1000w. Not really worth it for the hand full of times that call for such sustained amplifier output.
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post #46 of 215 Old 11-12-2010, 05:45 AM
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Originally Posted by Ricci View Post

Hey I agree Mark its certainly not impossible, but to put it into perspective even an AE TD15X or H, which is pretty durn efficient, much more so than the usual subwoofer driver through the 40-100hz range, in a roughly similar enclosure to the HSU, 5cu ft tuned to 24hz for a guess(about 5cu ft is the max volume that it could realistically be and tuning is probably 22-24hz with both ports open. (even lower tuning drops efficiency up high)) just barely falls short of the quoted numbers with the claimed 1400w (31.5dbw roughly). Sure a few pro drivers will come close to meeting that 123-125db spec but none of them have much more than 10-14mm xmax at most and you'll need more than that for the lower one port blocked tuning or the driver will run out of excursion at the peak above tuning. None of that is taking into account any sort of compression either.

I'm not saying the sub isn't or is a good performer BTW. Hell even if you chop 3 or 4db off of those quoted #'s it'd still be a whole lot of output for the size and money.



On the amplifier front it seems like a lot of amps are built with 3-6db of dynamic power these days (Its marketed as RMS or even continuous power still though) Powersoft, Lab Gruppen, etc... HSU should just join the club and call it a 1400w amp. Most any big multi KW amplifier placed on a 120v 15A or 20a circuit is going to be able to burst its rated power or more momentarily, but the ac line can't provide enough juice to sustain that kind of output so the continuous output is less. Most amps are being designed with short duration burst in mind instead of continuous output these days. They aren't overbuilt enough or meant to do sustained output at clipping so the output is limited to a lower level for longer duration signals, which makes sense really. On the other hand you have 1000w amps that will sit there and do 1000w for 1hr solid like my AE techron's but they are mono, 3 rack spaces and 92lbs each and eat most of a 20A circuit doing that lowly 1000w. Not really worth it for the hand full of times that call for such sustained amplifier output.

I'm only commenting because I see a disturbing trend that is steering us away from a decade of real design and progress and back to the dark ages of useless marketing jargon and misleading stats, aimed at the next generation of noobs.

The high 1W/1M, low Q drivers have much higher F3 (that's right, 3dB down point... NOT 6dB down point listed as +/-3dB) and are much less sensitive below 30Hz than real subwoofer drivers.

The internet direct and internet marketed sub world was completely dominated by Dr. Hsu and Tom Vodiodoh for a long time. Quite frankly, their subs were cheap and the performance was in line with that. Just compare the non-TV PB13 Ultra to the TV PB12 Ultra.

The DIY crowd inspired Stryke, Adire, AA, Epik, Ed, PE, Mach5 Audio, TC Sounds, Seaton, et al, to design and market better products that were geared toward HT performance.

We saw the evolution from 25Hz tune ported to 10Hz tune ported... more than an octave. We saw high Le camel hump FRs evolve to flat or room gain friendly roll off FRs. We saw the evolution from a single native response to user-selectable multi-response choices, including a low Q sealed option. We saw the advent of smaller sealed subs with much lower in-room extension and much more capable power plants. We saw the advent of on board and outboard EQ options.

Now, with the Chase stuff and this Hsu sub, we see much higher F3 and baloney output dB drag race numbers. These subs are bare bones 40-60Hz output numbers subs. Of course they sound "tighter", there's no low end. Duh. Their max output curves are high F3 sealed subwoofer FRs, yet, they claim flat to 20Hz FRs.

We're shifting backward to "bang-for-buck", "what did it hit on the RS meter?", "graphs are unnecessary eye candy", "anything below 20Hz is an artifact", "get 'x' sub, it'll blur your vision".

Hell, who couldn't do all that 15 years ago with a $500 2RU amp and a couple of pro sound 18s tuned to 30Hz? Sounds tight. Goes loud. Specs are BS.

I have a couple of Labs (and 1/2 dozen TD knock offs). They aren't capable of +6dB RMS to burst in a 20A circuit. But, compared to any 300W plate amp they're mythical gods of unspeakable thunder and awe.

I don't have a stackable 8x15" sealed system EQ'd by a custom made Marchand Bossobassis powered by state of the art amplification because I like think subwoofers are measured by the pound and how much hardware is in your rack.

I have clean, reference level low end across the entire LFE BW with any known source from a small footprint, very high quality system that my sons will enjoy when I'm dead and gone for less $$ than a videophile spends on this years most coveted video monitor.

I like Dr. Hsu and Pete's always been a great representative of his excellent company. I've purchased their products for friends and clients. But, please guys, market your new ported 1x15" sub for what it is... a great sub for the money in an attractive package. And, please, if you're going to tout the response, tell people the real max output numbers before the amp chokes on its tongue across the touted response. Show the response and roll off in both tunes. Then tout the burst numbers and advantages/disadvantages of such a design.

If you don't, we will. And, we'll employ educated guesses before we buy one.

Siegfried's shaped tone burst tests are a valuable tool for examining loudspeakers from several angles, but I fear it's soon to become (if not already) completely unrecognizable and twisted into a dB drag race tool.

http://www.linkwitzlab.com/Stereophi...20Linkwitz.htm (scroll to the discussion on his shaped tone burst)

Bosso
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post #47 of 215 Old 11-12-2010, 06:21 AM
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You sir have a ton of knowledge. I have the HSU VTF-3 MK3 and it sounds terrific in my "home theater room". It is great with music and makes my room shake and sway with HT. I also have two of the MFW-15's, and they have just sound ok to me. I just had one amp repaired by Murrel and the other one hums like crazy. And to be honest the MK3 is better for HT in my room.

I also have built the Kappa Perfects, and dual custom IXL 18.2.2's. But I always preferred the sound of the MK3. I really don't want or need a gillion db's in my room or house. I just want something that looks nice and plays nice, especially at modest volumes. I have always found that the MK3 did it for me. I guess what I am saying is that the VTF-15H not only looks great but I am sure that it will improve upon my MK3.

I certainly defer to your vast knowledge of the inner workings of a sub as this new sub has caused quite a stir. I do understand on whole what you are saying though.

regards..

Quote:
Originally Posted by bossobass View Post

I'm only commenting because I see a disturbing trend that is steering us away from a decade of real design and progress and back to the dark ages of useless marketing jargon and misleading stats, aimed at the next generation of noobs.

The high 1W/1M, low Q drivers have much higher F3 (that's right, 3dB down point... NOT 6dB down point listed as +/-3dB) and are much less sensitive below 30Hz than real subwoofer drivers.

The internet direct and internet marketed sub world was completely dominated by Dr. Hsu and Tom Vodiodoh for a long time. Quite frankly, their subs were cheap and the performance was in line with that. Just compare the non-TV PB13 Ultra to the TV PB12 Ultra.

The DIY crowd inspired Stryke, Adire, AA, Epik, Ed, PE, Mach5 Audio, TC Sounds, Seaton, et al, to design and market better products that were geared toward HT performance.

We saw the evolution from 25Hz tune ported to 10Hz tune ported... more than an octave. We saw high Le camel hump FRs evolve to flat or room gain friendly roll off FRs. We saw the evolution from a single native response to user-selectable multi-response choices, including a low Q sealed option. We saw the advent of smaller sealed subs with much lower in-room extension and much more capable power plants. We saw the advent of on board and outboard EQ options.

Now, with the Chase stuff and this Hsu sub, we see much higher F3 and baloney output dB drag race numbers. These subs are bare bones 40-60Hz output numbers subs. Of course they sound "tighter", there's no low end. Duh. Their max output curves are high F3 sealed subwoofer FRs, yet, they claim flat to 20Hz FRs.

We're shifting backward to "bang-for-buck", "what did it hit on the RS meter?", "graphs are unnecessary eye candy", "anything below 20Hz is an artifact", "get 'x' sub, it'll blur your vision".

Hell, who couldn't do all that 15 years ago with a $500 2RU amp and a couple of pro sound 18s tuned to 30Hz? Sounds tight. Goes loud. Specs are BS.

I have a couple of Labs (and 1/2 dozen TD knock offs). They aren't capable of +6dB RMS to burst in a 20A circuit. But, compared to any 300W plate amp they're mythical gods of unspeakable thunder and awe.

I don't have a stackable 8x15" sealed system EQ'd by a custom made Marchand Bossobassis powered by state of the art amplification because I like think subwoofers are measured by the pound and how much hardware is in your rack.

I have clean, reference level low end across the entire LFE BW with any known source from a small footprint, very high quality system that my sons will enjoy when I'm dead and gone for less $$ than a videophile spends on this years most coveted video monitor.

I like Dr. Hsu and Pete's always been a great representative of his excellent company. I've purchased their products for friends and clients. But, please guys, market your new ported 1x15" sub for what it is... a great sub for the money in an attractive package. And, please, if you're going to tout the response, tell people the real max output numbers before the amp chokes on its tongue across the touted response. Show the response and roll off in both tunes. Then tout the burst numbers and advantages/disadvantages of such a design.

If you don't, we will. And, we'll employ educated guesses before we buy one.

Siegfried's shaped tone burst tests are a valuable tool for examining loudspeakers from several angles, but I fear it's soon to become (if not already) completely unrecognizable and twisted into a dB drag race tool.

http://www.linkwitzlab.com/Stereophi...20Linkwitz.htm (scroll to the discussion on his shaped tone burst)

Bosso

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Originally Posted by bossobass View Post

I'm only commenting because I see a disturbing trend that is steering us away from a decade of real design and progress and back to the dark ages of useless marketing jargon and misleading stats, aimed at the next generation of noobs.

The high 1W/1M, low Q drivers have much higher F3 (that's right, 3dB down point... NOT 6dB down point listed as +/-3dB) and are much less sensitive below 30Hz than real subwoofer drivers.

The internet direct and internet marketed sub world was completely dominated by Dr. Hsu and Tom Vodiodoh for a long time. Quite frankly, their subs were cheap and the performance was in line with that. Just compare the non-TV PB13 Ultra to the TV PB12 Ultra.

The DIY crowd inspired Stryke, Adire, AA, Epik, Ed, PE, Mach5 Audio, TC Sounds, Seaton, et al, to design and market better products that were geared toward HT performance.

We saw the evolution from 25Hz tune ported to 10Hz tune ported... more than an octave. We saw high Le camel hump FRs evolve to flat or room gain friendly roll off FRs. We saw the evolution from a single native response to user-selectable multi-response choices, including a low Q sealed option. We saw the advent of smaller sealed subs with much lower in-room extension and much more capable power plants. We saw the advent of on board and outboard EQ options.

Now, with the Chase stuff and this Hsu sub, we see much higher F3 and baloney output dB drag race numbers. These subs are bare bones 40-60Hz output numbers subs. Of course they sound "tighter", there's no low end. Duh. Their max output curves are high F3 sealed subwoofer FRs, yet, they claim flat to 20Hz FRs.

We're shifting backward to "bang-for-buck", "what did it hit on the RS meter?", "graphs are unnecessary eye candy", "anything below 20Hz is an artifact", "get 'x' sub, it'll blur your vision".

Hell, who couldn't do all that 15 years ago with a $500 2RU amp and a couple of pro sound 18s tuned to 30Hz? Sounds tight. Goes loud. Specs are BS.

I have a couple of Labs (and 1/2 dozen TD knock offs). They aren't capable of +6dB RMS to burst in a 20A circuit. But, compared to any 300W plate amp they're mythical gods of unspeakable thunder and awe.

I don't have a stackable 8x15" sealed system EQ'd by a custom made Marchand Bossobassis powered by state of the art amplification because I like think subwoofers are measured by the pound and how much hardware is in your rack.

I have clean, reference level low end across the entire LFE BW with any known source from a small footprint, very high quality system that my sons will enjoy when I'm dead and gone for less $$ than a videophile spends on this years most coveted video monitor.

I like Dr. Hsu and Pete's always been a great representative of his excellent company. I've purchased their products for friends and clients. But, please guys, market your new ported 1x15" sub for what it is... a great sub for the money in an attractive package. And, please, if you're going to tout the response, tell people the real max output numbers before the amp chokes on its tongue across the touted response. Show the response and roll off in both tunes. Then tout the burst numbers and advantages/disadvantages of such a design.

If you don't, we will. And, we'll employ educated guesses before we buy one.

Siegfried's shaped tone burst tests are a valuable tool for examining loudspeakers from several angles, but I fear it's soon to become (if not already) completely unrecognizable and twisted into a dB drag race tool.

http://www.linkwitzlab.com/Stereophi...20Linkwitz.htm (scroll to the discussion on his shaped tone burst)

Bosso

Nice rant, but here's the issue:

99% of the people who purchase subwoofers don't have the knowledge you do (I'm one of them). We're out there spending $500+ on these things... how in the world with all these different factors (watts, woofer size, enclosure dimensions, port size) are we supposed to come to a correct conclusion on what's the perfect sub for us? The CEA2010 gives us SOMETHING to help compare these products.

If someone posts "I have a $500 budget in a 4000 cu ft room..." every fanboi swears their subs are the best like they are rooting for their football team. I don't see any magazines sticking their necks out and offering us non-fluffy information. Guys like you sit on the sidelines and don't offer us any objective charts to good subs in price ranges.

You've really got nothing to cry about when it comes to the CEA2010 standards. At least someone out there is trying to give us less knowlegeable sort something to compare these subwoofers with, even if it's not perfect.
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Didn't Ikka use the same tests that we all use as gospel?
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Nice rant, but here's the issue:

99% of the people who purchase subwoofers don't have the knowledge you do (I'm one of them). We're out there spending $500+ on these things... how in the world with all these different factors (watts, woofer size, enclosure dimensions, port size) are we supposed to come to a correct conclusion on what's the perfect sub for us? The CEA2010 gives us SOMETHING to help compare these products.

If someone posts "I have a $500 budget in a 4000 cu ft room..." every fanboi swears their subs are the best like they are rooting for their football team. I don't see any magazines sticking their necks out and offering us non-fluffy information. Guys like you sit on the sidelines and don't offer us any objective charts to good subs in price ranges.

You've really got nothing to cry about when it comes to the CEA2010 standards. At least someone out there is trying to give us less knowlegeable sort something to compare these subwoofers with, even if it's not perfect.

99% of people shop at Best Buy, not AVS forums. If you're going to take on the mantle of the people's representative, have some real data to present.

What exactly doe the CEA standard give you, just out of curiosity and since you apparently represent 99% of AV consumers?

I appreciate your synopsis of my 8 years here posting on the subject, answering thousands of e-mails and PMs from countless folks who do diligent research before they whip out their credit cards.

Bosso
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Didn't Ikka use the same tests that we all use as gospel?

Yes. Send him some subs so we can see the results.

Bosso
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Didn't Ikka use the same tests that we all use as gospel?

His testing and measurements sure, but not everyone was fond of him adding CEA.
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Yes. Send him some subs so we can see the results.

Bosso

He works for Genelec now, we need a replacement. I never liked ground plane measurements. Front firing with front ported would be at an advantage but not in a room. Having said that they are what they are and still adds some data.
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Originally Posted by bossobass View Post

Yes. Send him some subs so we can see the results.

Bosso

I was in UPS last week and someone was going to ship a 78lb box of clothes to Germany. The quote was $610.00. Needless to say the guy left without shipping it.
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He works for Genelec now, we need a replacement. I never liked ground plane measurements. Front firing with front ported would be at an advantage but not in a room. Having said that they are what they are and still adds some data.

Yes, I know. I stay in touch with the Ilkster through e-mail.

I agree with you in principle, but Ilkka's results were without any bias and had the main advantage of direct comparison with all of the subs he tested across the entire range of his battery of tests, unlike cherry-picked numbers from manufacturers, which can certainly be misleading.

Let's not leave out Charlie/Slartibartfast/My Name Isn't Important from AVTalk, who is certainly on a par with Ilkka. I'm not sure if he still cares to test subs, but it wouldn't hurt to ping him.

IMO, seeing the results from him would go a long way to showing the differences between all of the current slate of recently released subs from Chase, Epik, Hsu, Ed, Lava, Rythmik, SVS, etc, vs all of the subjective banter that is the alternative.

Bosso
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post #56 of 215 Old 11-12-2010, 08:18 AM
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I'm not saying the sub isn't or is a good performer BTW. Hell even if you chop 3 or 4db off of those quoted #'s it'd still be a whole lot of output for the size and money.

I think this POV is key...Ricci posted it but I think we do agree.

Most people are not going to care about the nitty gritty details but some of us do...some like to dot the Is and cross the Ts when it comes to performance numbers.

The general user (most found on the subwoofer forum) we see this discussion as an attack on the product because really all they ever want is for people to post this sub and that sub sound amazing, they want subjective high fives and fluffy descriptions on performance.

None of the critical thinking stuff really matters, no one cares what driver was used to get the results and what compromises exist in that driver. They just want their cake with subjective Icing.

Yes in the clean output / $$$ is a great purchase but does that mean nothing can be discussed with a critical eye?

Atleast we have DIY to do so

Im pretty sure lots of posts have happened since I posted on the HSU thread. Those will have to wait until the weekend no time to humor myself on all the stone throwing replies that Im sure will exist

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post #57 of 215 Old 11-12-2010, 08:19 AM
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Originally Posted by bossobass View Post

Yes, I know. I stay in touch with the Ilkster through e-mail.

I agree with you in principle, but Ilkka's results were without any bias and had the main advantage of direct comparison with all of the subs he tested across the entire range of his battery of tests, unlike cherry-picked numbers from manufacturers, which can certainly be misleading.

Let's not leave out Charlie/Slartibartfast/My Name Isn't Important from AVTalk, who is certainly on a par with Ilkka. I'm not sure if he still cares to test subs, but it wouldn't hurt to ping him.

IMO, seeing the results from him would go a long way to showing the differences between all of the current slate of recently released subs from Chase, Epik, Hsu, Ed, Lava, Rythmik, SVS, etc, vs all of the subjective banter that is the alternative.

Bosso

I agree!!
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post #58 of 215 Old 11-12-2010, 08:24 AM
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Nice rant, but here's the issue:
...... Guys like you sit on the sidelines ......

Guys like Bosso sit on the sidelines???

Wow, that could not be further from the truth, Guys like Bosso push the subwoofer envelop further then any one else I know. Well accept for Thomas W. who runs the IB Cult forum.

You should ask Craig where most of his opinions about about dual sealed subs came from. Of course Craig will NEVER admit it in an open forum but lets not forget how long Bosso has been leading everyone down the sealed design path.

To say Bosso sits on the side lines is grossly inaccurate.

He is building and testing and answering PMs all the time just what else would you like him to do??


I mean the stuff Ricci, Bosso and Mark Seaton are posting is incredible stuff, you can not pay enough for this type of info..IMO!!

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post #59 of 215 Old 11-12-2010, 08:24 AM
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Originally Posted by bossobass View Post

I appreciate the post, but I understand the difference.

It's my opinion that the max output numbers should form a curve that resembles the claimed native frequency response magnitude. When there is a large disparity between the two, the claimed native response ceases to have much meaning.

I can dial in a ruler flat response to 9Hz with the Bassis, but then throw the max output numbers out the window, because the amp will run out of gas far before the max output at 63Hz can be used.

If I employ limiters to prevent that from happening, the max output curve no longer even closely resembles the published FR curve, as in the Velo DD-18:



Max clean output, in the context of FR, resides at the subs weakest point, not its strongest point. A distinction should be made, especially when a huge disparity between the two exists, or max output at 'x' frequency specs should not be included.

Bosso

You are definitely correct that a distinction should be made, and that is precisely why Keith Yates and later Ilkka included both swept sine measurements as well as peak burst output. Don Keele was one of the first to really use the shaped tone burst and this was seen in many reviews he did for I believe Audio Magazine back in the 90s or earlier. It is a useful bit of information to know, but as I've been emphasizing, one metric will never give a clear picture of what will be heard.

These practical limits on a ~20-30 second, downward swept sine wave measurement at increasing levels will contrast with the burst power just as would a torque vs. HP vs. RPM curve. I'd request we please not go too far into the annoying car analogies as the important point here is that you need both metrics to get a clear picture of certain behavior. In both cases of audio and auto, where all design aspects are similar you will see much more consistent relations between different metrics. As different designs are compared, we start seeing the assumptions for one specific design implementation fall apart. You can no longer draw confident conclusions from a single metric.

Your example with the Bassis is a perfect one, as any manufacturer will have the ability to employ any EQ they like. The measurements showing burst power and increasing swept sine measurements into clipping would clearly show the design trade offs of twisting the dial for a 9Hz corner (outdoors) vs. a 25Hz corner. While the useful playback limits will be different for each of these low corners, the limit on the 9Hz system will be entirely dependent on the content you are playing. If we know the maximum capabilities per frequency, separate from the frequency response, we can then get an idea of how a subwoofer will handle certain passages. Just playing back a typically recorded rock & roll kick drum, the 9Hz & 25Hz dialed subs will be pretty close in playback limits, while the 9Hz choice will reach its limits much sooner playing War of the Worlds (but sound much more exciting while doing so ).

There's no reason a vented subwoofer can't have a naked response (pre-internal EQ/ ie response from constant Voltage vs. frequency) which rises 6-12dB from LF tuning to the upper octave of its intended range. It hadn't been a common choice to DIYers, but it's hardly new. That rise can be perfectly EQ'd out. Basic circuit analysis shows that a LT is in fact the perfect tool for that job. Add a 2nd order high pass below tuning for excursion protection and you can dial in any response shape of any driver tied to the box tuning frequency.

I intently did exactly this in the ill-produced MFW-15, and the set of strengths/limits that resulted in was very much part of what many enjoyed in its performance. If you aren't locked into off the shelf drivers parameters can be adjusted and you see that there can be design choices to make of gaining 6-12dB in sensitivity in the upper octave at the expense of 0.5-2dB in sensitivity at the tuning frequency depending on how well the drivers are optimized to the enclosure. There are certainly benefits to using 2-10x the power and a driver with a more flat naked response, but those benefits come at a monetary cost that each buyer and designer have to weigh out for themselves.

Mark Seaton
Seaton Sound, Inc.
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Originally Posted by bossobass View Post

99% of people shop at Best Buy, not AVS forums. If you're going to take on the mantle of the people's representative, have some real data to present.

What exactly doe the CEA standard give you, just out of curiosity and since you apparently represent 99% of AV consumers?

I appreciate your synopsis of my 8 years here posting on the subject, answering thousands of e-mails and PMs from countless folks who do diligent research before they whip out their credit cards.

Bosso

When did I say I represented 99% of AV consumers? I did say:
Quote:
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99% of the people who purchase subwoofers don't have the knowledge you do (I'm one of them).

Did I overestimate your knowledge of Subwoofers? Please correct me if I did. You're doing a better job of twisting words than the sub manufacturers that you accuse of twisting specs.

IM's are great, but there's certainly better tools to relay that information to the masses then IM's. You just sat there and ranted that things were going back to the dark ages of subwoofer marketing jargon, but you're not willing to stick your neck out and let us 'noobs' know what's what with subwoofers. You're part of the problem IMO on why this so called backward marketing step has happened.

CEA2010 isn't a perfect scale (I've read what you and Craig have said, i'm in no position to disagree), but it's a tool for us 'newbs' to utilize until so called 'experts' like yourself grow a pair and don't worry about stepping on toes and express your findings to the masses, not just your internet buddies.
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