Official Craigsub rankings thread - Page 31 - AVS Forum
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post #901 of 6764 Old 01-29-2007, 03:55 PM
 
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Originally Posted by cyberbri View Post

And you seem to have declined to test one yourself paid for with your own money. There's a 30-day return period, so you wouldn't be out much $. Or you could go to his house and see the test performed in person. That would seem more logical than asking someone to ship his sub to you so you can test it because you don't believe the results of the test.

Why would I need to do that? I am not an "Official" subwoofer reviewer.

Also, if you are trying to get to the bottom of an unusual issue it might make sense to OPENLY look into the matter. It would be necessary to have the device in question. But this device is not available to others! It would be nice to compare it to a known properly performing device, another sample. And it would help to have dialog with the official reviewer as well as the manufacturer. Come to think of it maybe a few testers should be involved. Other stuff. Including the blind test information and procedures for these reviews. Perhaps some of the participants could comment here. Was this "limiter" issue of audible significance to them? Was it tested?

For starters, complete test information would help. Maybe Craigsub contacted the manufacturer already as to this unusual 14-18 dB attenuation issue, I may have missed his comments in these regards. From the comments I see here, it seems like the manufacturer does not think the device should be cutting 14-18 dBs of output when the limiter kicks in.
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post #902 of 6764 Old 01-29-2007, 03:57 PM
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Quote:
Originally Posted by cyberbri View Post

And you seem to have declined to test one yourself paid for with your own money. There's a 30-day return period, so you wouldn't be out much $. Or you could go to his house and see the test performed in person. That would seem more logical than asking someone to ship his sub to you so you can test it because you don't believe the results of the test.

Seriously, just BUY some subs and test them....you can even return them like mentioned!

OR

HELL if you have the equipment and everything you need to test with I will invite you over my house, we can have a get together and test the **** out of my PB-12NSD.


PS...your "official" comment was not needed, its things like that that get us all fired up at you. Its called the official craigsub list because it was the list copied from another forum. It has nothing to do really with Craig being official or not official!

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post #903 of 6764 Old 01-29-2007, 04:09 PM
 
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Originally Posted by bgillyjcu View Post

PS...your "official" comment was not needed, its things like that that get us all fired up at you. Its called the official craigsub list because it was the list copied from another forum. It has nothing to do really with Craig being official or not official!

So this is not "Official", ha? Thanks for clarifying the matter. Calling it official seems misleading to me. The admins I corresponded with did not clarify this point.
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post #904 of 6764 Old 01-29-2007, 04:10 PM
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Originally Posted by sjmarcy View Post

Why would I need to do that? I am not an "Official" subwoofer reviewer.


Neither is craig. And yet you hold him to professional standards, and ask him to send you HIS OWN sub. Same thing. You want to test it yourself, test a different one of the same model. Simple as that.

Quote:


Also, if you are trying to get to the bottom of an unusual issue it might make sense to OPENLY look into the matter. It would be necessary to have the device in question. But this device is not available. It would be nice to compare it to a known properly performing device, another sample.

And out of all your advice, you haven't suggested sending it back or trying another one. Neither has SVS.

Quote:


And it would help to have dialog with the official reviewer

There is no "official reviewer," if you will kindly recall. This is one man doing this as a hobby and sharing graphs and impressions with everyone else.


It is odd that you are more bent out of shape about the SVS's performance than SVS themselves. If it's not expected behavior, why haven't they chimed in and said so and offered to give him a new sub that performs to spec?

Why using other people's TV settings is a
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post #905 of 6764 Old 01-29-2007, 04:11 PM
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Originally Posted by sjmarcy View Post

So this is not "Official", ha? Thanks for clarifying the matter. Calling it official seems misleading to me. The admins I corresponded with did not clarify this point.


This has been explained several times to you. This is the "official" thread for craig's "impressions" and graphs, results, etc., started by someone completely other than craig himself.

Why using other people's TV settings is a
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post #906 of 6764 Old 01-29-2007, 04:25 PM
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I think I'm going to start the
""Official" "Official" subwoofer testing thread conducted by those who choose to buy the subwoofers and test them solely because they love doing it.


CRAIG will be the first poster I hope

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post #907 of 6764 Old 01-29-2007, 04:46 PM
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In the real world, circuits go through revisions, and pick and place machines get loaded with the wrong parts. I'm starting to suspect that there may be differences between the average sub of the model Craig has been working with, and HIS SPECIFIC UNIT. In that sense sjmarcy has brought up a good issue, that more data points might confirm or reject this being a model-wide issue.

My thinking has evolved to this point on subs. In order to make certain things start to really work in the bass-head's favor, we should be thinking in terms of PERCENT OF ROOM VOLUME MODULATION. The sad fact is, one 12", 15", 18" simply has near-zero coupling to the acoustic load of 15PSI air at frequencies below 40Hz or so. Even when you add in ports, the theoretical surface only doubles. Relying on room gain to boost bass performance actually smears transient pressures into multi millisecond slop, ruining the chance of summing with higher harmonics from an actual sound source (some people call this "integration"). Have you guys ever noticed the Thiel/Small parameters changing for multiple subs in a co-located position? I see the industry moving towards ever longer throws and lower efficiency, needing killoWatt amplifiers to get them moving, and truly monstrous costs to produce drivers with greater than 1" Xmax. Unless some kind of positional servo is applied, suspension non-linearities get worse with throw distance. Servo circuits introduce group delay, as do AtoD & DSP to DtoA front ends.

The solution? An assload of drivers! Instead of fighting at the edge of physics, take that same 1000Watt amp and run it into eight 12" drivers with more reasonable proportions of voice coil length, stupid big magnets, and nice rise and settling times in 0.5Qb - 0.707Qb. Let magnets do some of the work for you. A small part of me admires the engineering effort and manufacturing skill put into drivers from firms like TC sounds and Adire, but enough is enough. The law of diminishing returns is forcing us to argue that this subwoofer puts out 2dB more than that, instead of talking about 10-20dB increases through proper acoustical impedance matching. One of my larger club installations had [32] sealed 12" woofers in coffin sized boxes, covering 64 square feet of baffle area. Each enclosure had [4] drivers, and the whole bass system was run by a couple of Crown Macros. I remember subtle shifts in the position of my internal organs on the right notes in some dance music. PUT THAT IN YOUR HOUSE ALREADY! At the point that some people have dedicated rooms for theaters, making a whole wall 12" thicker and just filling it with drivers is not only practical, but seems logical to me. If your GF or wife really hates it that much, well...

I'm proposing 1% to 2% atmospheric modulation as a goal to reach truly authoritative low frequency performance. I bet you'll find that standing waves essentially go away because of the continuum of driver placement, and a certain fear of turning up your subs 12dB hot will grip your heart. Since room gain smears transients with "false" output, the new coupling will instead deliver cycle for cycle accurate SLAM, so when a dump truck falls off a bridge in some Bruckheimer flick, you'll be looking up the number to your home insurance broker to see if you've got earthquake coverage. Since you'll finally have excess bass energy to spare, one will be able to use bass traps and other room placement tricks to reduce boundary reinforcement in favor of more accurate impulse timings.

Some of the discussions on this forum remind me of VW Bug owners calling their car dealers to get upgrade suggestions so they can tow a Bayliner. In many ways, we're asking the wrong questions...

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post #908 of 6764 Old 01-29-2007, 04:50 PM
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Quote:
Originally Posted by sjmarcy View Post

Bear in mind that experienced reviewers test and listen for more things than get published. A 14-18 dB drop when the limiter kicks in was not found. Maybe the S&V reviews have some issues? I note that their recent tests of a JL F112 sub showed it did not have much deep, clean bass. It maxed out at 80 dB at 16 hz. Maybe this unit is much less capable than the larger unit.

That leaves Cragsub as the only reviewer noting this problem. If we look into the matter further as to how he found such gigantic drops in output from a particular device it would help out the group is my view. Maybe Tom Nousaine needs to greatly revise his battery of tests? Or maybe the unusual behavior was a measurement issue. Or perhaps it's just not a real issue for some reason. We haven't enough information to know this.

However, if as I have asked repeatedly, Craigsub's procedures and processes were sufficiently documented such that others can repeat the test to confirm his discovery...this would be helpful and informative. I am happy to test the exact sub he tested, but this offer was apparently declined.

Who wouldn't decline such an offer accompanied by such a supercilious tone?

This is not a knock on Tom Nousaine but anyone following the JL113 trread would know that something was amiss with TN's initial measurements, which were inconsistent with JL's tests and the reports of various posters. His results were anemic compared to the Fathom's actual output. The inital measurements were removed and replaced several weeks later with more accurate results. These things happen but no explanation was forthcoming.

Does TN need to revise his tests? Beats me. Probably not. But lets compare apples with apples.

The observed behaviour was with a movie scene with complex dynamics not a predicatable frequency sweeps which are simple crude approximations of the demands placed on subs in film soundtracks. I've seen similar reports of strange behaviour with sweeps and tones with other subs. There has been enough discussion about the limiter suggesting its implementation is overaggressive in applying brakes. At this point that would appear to be the cause of the discrepancy. It was explained well by LowOrder earlier, assuming this is still his position:

Quote:


It's important to note that the reason the "green" sweep only falls behind -4dB below 20Hz is due to some possible element of GAIN in the system for low frequency assistance? Alternatively, the limiter maybe has a frequency shaping network on the control signal side, and makes inputs below 20Hz more strongly limit the whole band than inputs well above 20Hz in frequency. Thus the sweep nature of the test signal HIDES compression of the whole bandwidth in the presence of strong information below 20Hz.

I suspect that the scene Craig is using for his AVERAGE ENERGY has a particular order of appearance of tones, such that significant energy in the 45Hz band comes on the heels of some crazy tones below 20Hz. So you would get:

#1 20Hz wallop

#2 some 45Hz info -4dB down

But the stuff before and after stays at a decent level, unsquashed by the limiter away from the big bang at <20Hz. There is some danger using sweeps because the simplified nature of the input signal may hide complex behavior. That said, it isn't a severe error, but a larger one than the high-to-low frequency "green" sweep suggest. I'm impressed Craig's alternate methodology has added a tool for quantifying dynamic signal behavior of limiters


John
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post #909 of 6764 Old 01-29-2007, 05:03 PM
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Originally Posted by sjmarcy View Post

So this is not "Official", ha? Thanks for clarifying the matter. Calling it official seems misleading to me. The admins I corresponded with did not clarify this point.

sjmarcy

I don't believe that Craig even started this thread. I have been trying to figure out why you continue to agitate. Are you just going to keep it up to see how thick a skin Craig has? Or maybe to the point that he just picks up his marbles and says the heck with it? Would that be some kind of victory for you? For somebody else? I can't figure another reason. These are subwoofers. It's a hobby for crying out loud.

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post #910 of 6764 Old 01-29-2007, 05:11 PM
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If you do not like what Marcy says report him.

Craig knows better than to let someone with some sort of secrete plan or something stop him from doing what he likes, which is testing his Audio Equipment. Craig knows he has a STRONG following here and we support and THANK him for everything he does that we all wish we could do!

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post #911 of 6764 Old 01-29-2007, 05:59 PM
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LowOrder,

32 sealed 12" subs in coffinsized boxes? Sign me UP!!

That's gotta be one serious setup. Yet another system for me to be jealous of.

I guess I'll just have to settle for less. Out of curiousity, how much $$$$ for something like that?
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post #912 of 6764 Old 01-29-2007, 06:25 PM
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John, a system like that you'd be looking at $26,000 not including processing and amplifiers. To be fair, since it was a one-off project I really wanted to do, I think the actual price was closer to $12,000 for drivers, enclosures, delivery and installation. The client did much of the enclosure work themselves, once the plans and proto were built. Yes, I am THAT lazy!

My previous post only seems ridiculous, until you consider that at a mere $50 a week, a person could set aside for say, [4-5] nice little sealed subs like the SVS SB12+ a year. In a couple of years, you'd be up to EIGHT boxes, never see or hear the limiters, and have lovely distributed room placement options. Suddenly $5000 at a rate less than half the monthly payment of a subcompact car from Korea seems doable even if you eat at Taco Bell. Bet you could even get a discount!

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post #913 of 6764 Old 01-29-2007, 06:36 PM
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Quote:
Originally Posted by LowOrder View Post

...edit...
My thinking has evolved to this point on subs. In order to make certain things start to really work in the bass-head's favor, we should be thinking in terms of PERCENT OF ROOM VOLUME MODULATION. The sad fact is, one 12", 15", 18" simply has near-zero coupling to the acoustic load of 15PSI air at frequencies below 40Hz or so.
...edit...
The solution? An assload of drivers! Instead of fighting at the edge of physics, take that same 1000Watt amp and run it into eight 12" drivers with more reasonable proportions of voice coil length, stupid big magnets, and nice rise and settling times in 0.5Qb - 0.707Qb. Let magnets do some of the work for you.
...edit...

That's my POV as well. If you are not going to build a horn to act as the transformer between the driver and the atmosphere, your other option is to directly drive a surface equal to the mouth area of the horn.

I also think we're going to have to divide up the bass frequencies at say 25Hz so that driver solutions can be optimized, and to reduce intermodulation distortion.
This Elemental Designs video has folks in the ED thread oohing and aahing about extention -- it's the best visual depiction of how IM happens I've ever seen:
http://edesignaudio.com/edv2/13kv2_video.php
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post #914 of 6764 Old 01-29-2007, 06:48 PM
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Quote:
Originally Posted by bgillyjcu View Post

If you do not like what Marcy says report him.

Have you?

By the way, I glanced at your "HT" - is that the SVS HTITB with the upgraded sub?

Most people don't know what they want...but, they're pretty sure they haven't got it. ©

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post #915 of 6764 Old 01-29-2007, 07:25 PM
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Craig,

Keep up the great work,if some question your work...let them show by example and start a serious work and lets see how they do.Before their little fingers start to question your work.

I would ignore the plaintifs,unless they bring some positive info to the table that will help a good deal your testing,or the accuracy. So far from what I see(numbers)you are on target.

Negative people are best ...ignored.



LowOrder,

Agree with you,to get real slam,and negate the negative effects of room acoustics you use an apropriate amount of woofers/subs to pressurize the room. This goal I am very close in a 800cu ft space,using multiple capable subs(JL,Velo,Revel and company).In a 1000cu ft room I would say four f113 will start to do,for bass that is so palpable you will feel air be pushed in and out of your lungs. Who needs tactile transducers to shake a sofa when you have the real deal.

My goal will be met this summer(I hope)when JL releases the GOTHAM,by then dual f112,dual f113 and a single GOTHAM should energise a space under 800cu ft the way I want.If not...another GOTHAM.Modesty not a chance,bring out the big gunns.

Ask yourself mortal , do you have as much displacement as me ? The answer is no unless you have a Windmere fan sub.
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post #916 of 6764 Old 01-29-2007, 07:25 PM
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Ggunnell,

That was a funny video! You can actually see the surround start to deform, suggesting possible cavitation in an enclosure. The effect you are referring to is called Doppler Distortion, caused by the forward and back velocity of the cone frequency modulating a higher tone (thus IM). While I don't want to return to the good old days of accordion surrounds and 3mm of Xmax, I think a healthy Xmax of 6-12mm, and a very high "no" number >2 coupled with appropriate cumulative surface area (as you referred to a bass horn cross section) is a great formula. I've been sniffing around at the 16Ohm driver idea, as the turns-in-the-gap density leads to astounding Bl numbers. I find it hilarious that people are all ooh-ing and aah-ing at better than 80% efficient non-linear switching amps, while hooking them up to ever less efficient drivers because the magnetic field is stretched so thin over such an obnoxiously long winding. Remember, at a given impedance, a longer winding length means fewer turns in the field. The Lorentz Force is thus diminished.

Build a driver that sneaks up against its stops at 100W-200W, 16Ohms. Put it into a box spring that has a 0.5Qb. Provide reverse transfer function compensation EQ at minimum phase to an arbitrary low frequency f-3dB. Repeat...

Incidentally, some of my drivers have a Qts around 0.15. Even with a loose suspension and Fs around 20Hz, by the time you get into the 16Ohm range, you might be as low as Qts = 0.1; Vas to Vb ratio is then about 24 times! That is one tiny box.

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post #917 of 6764 Old 01-29-2007, 07:48 PM
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Regarding HSU, what does MK mean and what is difference between II and III. Thanks
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post #918 of 6764 Old 01-29-2007, 07:55 PM
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sjmarcy, this is your FINAL warning.

Take a vacation from THIS thread or take a permanent vacation from AVS.
Your choice.

I will not allow you to continue de-railing this thread.

Kyser

PS - Guys, ignore this and get back on topic.

Thanks,

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post #919 of 6764 Old 01-29-2007, 07:55 PM
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Quote:
Originally Posted by ggunnell View Post

I also think we're going to have to divide up the bass frequencies at say 25Hz so that driver solutions can be optimized, and to reduce intermodulation distortion.

.

I like your suggestion and have tried it several times in a multi-sub setup by assigning different subs a narrow frequency range. One sub to 30hz, another 30hz- 60hz and still another to 60hz- 90hz for example. Nice cleaner sound with fewer audible artifacts. HSU's MSM is a step in that direction because it has effectively spliced the band and by doing so eased the demands on the sub amps.

Some people call compression the silent killer but I've always felt that IMD is the more neferious killer of sound quality and the more difficult one to measure in subwoofers. IMD subwoofer measurements that have been posted at other forums have been a valiant effort, but two closely spaced tones in the 60hz-70hz zone are going to create a mish mash of THD and modulation products which only very sophisticated equipment will be able to completely separate. Its funny to read the complements for inaccurate results derived faulty methodology. No surprise that some researchers seem to conclude that THD and IMD are so closely related to be almost one in the same. It doesn't work that way.

John
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post #920 of 6764 Old 01-29-2007, 08:00 PM
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Quote:
Originally Posted by TheEAR View Post

Agree with you,to get real slam,and negate the negative effects of room acoustics you use an apropriate amount of woofers/subs to pressurize the room. This goal I am very close in a 800cu ft space,using multiple capable subs(JL,Velo,Revel and company).In a 1000cu ft room I would say four f113 will start to do,for bass that is so palpable you will feel air be pushed in and out of your lungs. Who needs tactile transducers to shake a sofa when you have the real deal.

My goal will be met this summer(I hope)when JL releases the GOTHAM,by then dual f112,dual f113 and a single GOTHAM should energise a space under 800cu ft the way I want.If not...another GOTHAM.Modesty not a chance,bring out the big gunns.

You know Ear, there are cheaper ways to build an atmospheric pressure chamber.

John
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post #921 of 6764 Old 01-29-2007, 08:00 PM
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Quote:
Originally Posted by meariesguy View Post

Regarding HSU, what does MK mean and what is difference between II and III. Thanks

MK refers to the word, "Mark" as in, version (as far as I know. I could refer to Peter Marcks of Hsu, ahaha.

This info may help you to begin sorting out the differences:

http://forum.hsuresearch.com/showpos...4&postcount=69

From this thread: http://forum.hsuresearch.com/showthread.php?t=2381

- Jon
"010 Meh"
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post #922 of 6764 Old 01-29-2007, 08:04 PM
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Quote:
Originally Posted by jakeman View Post

.

I like your suggestion and have tried it several times in a multi-sub setup by assigning different subs a narrow frequency range. One sub to 30hz, another 30hz- 60hz and still another to 60hz- 90hz for example. Nice cleaner sound with fewer audible artifacts. HSU's MSM is a step in that direction because it has effectively spliced the band and by doing so eased the demands on the sub amps.

Some people call compression the silent killer but I've always felt that IMD is the more neferious killer of sound quality and the more difficult one to measure in subwoofers. IMD subwoofer measurements that have been posted at other forums have been a valiant effort, but two closely spaced tones in the 60hz-70hz zone are going to create a mish mash of THD and modulation products which only very sophisticated equipment will be able to completely separate. Its funny to read the complements for inaccurate results derived faulty methodology. No surprise that some researchers seem to conclude that THD and IMD are so closely related to be almost one in the same. It doesn't work that way.

Maybe I'm coming out of left field here, and I apologize if it's been mentioned before - but maybe a form of IMD (intermodulation distortion) has something to do with the limiting effect on the PB-12NSD which has been discussed ad nauseum.

I'm wondering if that once the driver was pushed to it's limits in the deep bass range (~20hz), that besides having the amp begin limiting it also became impaired at reproducing some higher frequencies. Any chance of that?

Edit - Hmm...~23hz had the peak spl for the scene, ~46hz (2nd harmonic) had limiting...I wonder what ~69 (3rd harmonic) or ~92hz (4th harmonic) looked like....

- Jon
"010 Meh"
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post #923 of 6764 Old 01-29-2007, 08:25 PM
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Jon,

Its an interesting point you make, that as you run out of excursion, higher frequencies that are additive in phase with the crest of the fundamental are "pushed out" to the no-displacement-left zone. Bi-amplification has a similar effect on the headroom of power amplifiers. Bridging one of my Crown K2 amps at 2500W into 4Ohms and hooking it up to the sub PASSIVELY and running to similar output levels could confirm your theory. This would avoid any chance of amplifier clipping before the driver just commits suicide, as nearly any driver would.

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post #924 of 6764 Old 01-29-2007, 08:51 PM
 
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The Haunting DVD-DTS is on its way ... this should make for some more interesting graphs, especially with the waterfall chart handy.
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post #925 of 6764 Old 01-29-2007, 09:18 PM
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Quote:
Originally Posted by LowOrder View Post

Jon,

Its an interesting point you make, that as you run out of excursion, higher frequencies that are additive in phase with the crest of the fundamental are "pushed out" to the no-displacement-left zone. Bi-amplification has a similar effect on the headroom of power amplifiers. Bridging one of my Crown K2 amps at 2500W into 4Ohms and hooking it up to the sub PASSIVELY and running to similar output levels could confirm your theory. This would avoid any chance of amplifier clipping before the driver just commits suicide, as nearly any driver would.


Well, what are you waiting for?

- Jon
"010 Meh"
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post #926 of 6764 Old 01-29-2007, 09:24 PM
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Haha, I don't actually own any products made by SVS, Craig does. I was suggesting a protocol to eliminate the amplifier variable.

As I'm under the conceit "I can do better" I only own subs that are a result of my own design work. Lets just say my menagerie would raise some eyebrows...

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post #927 of 6764 Old 01-29-2007, 09:43 PM
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Consider my eyebrows ready to be raised. Pics please.
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post #928 of 6764 Old 01-29-2007, 10:08 PM
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I'm not ready to unveil my own madness. To reward your future patience, I will instead share someone else's efforts that will give a sense of scale of my own undertaking. I don't espouse this approach, architectural complications being but one of many objections. However, I've got to give Kudos hands down simply for the LEVEL OF COMMITMENT (pun intentional) shown by this guy...

http://www.royaldevice.com/custom.htm



Try to ignore the crazy theories, most of which don't hold water in my opinion. In one crucial way, the SHEER SIZE of his subs, he hits it OUT OF THE PARK.
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post #929 of 6764 Old 01-29-2007, 11:44 PM
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Craigsub,

Thanks for all the hard work in reviewing these subs. I, for one, really appreciate the effort.

Based partly on your reviews, I recently purchased a HSU VTF3.3 and I'm very happy. It really pressurizes the 14'x30' room nicely! Now I just have to figure out how to keep the pictures from falling off the walls!
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post #930 of 6764 Old 01-30-2007, 03:32 AM
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Craig is welcome to exchange the PB12-NSD, but by all his subjective accounts, it is working fine.

Note, no where in this thread have I questioned Craig's objective data - I believe that graph is what TrueRTA spit out on that passage, and that is what Craig posted.

The real question to answer is what combination of variables resulted in this particular graph. It could very well be a combination of in-room FR, limiter activity, even the software itself. If I was present, we could try to duplicate the experiment and systematically eliminate/control variables and finger the culprit. Until such time all we can do is speculate - and we've seen that isn't terribly productive.

I might be able to break away for a day or two for Craig's next GTG, and I'll bring down my laptop and mic with various software programs and we can run some in-room and ground plane tests. Even then, Craig's reviews are more about in-room subjective and blind testing than they are about rigorous objective test data - and IMO we should focus more on the former and less on the latter.

Ed Mullen
Director - Technology and Customer Relations
SVS

"What We Do In Life, Echoes In Eternity"

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