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Are three inexpensive subs better than one expensive sub-Dr. Earl Geddes Approach - Page 2

post #31 of 2011
Quote:


This is humorous since I usually rely only on measurements and everyone says -"Its not the measurements that count but what it sounds like!"

First, I had never met any of the people who's reviews are posted on my website prior to their visit, so they came with no "bias", only an open mind. So if there was any bias it could only be because of my charming and magnetic personality which, for those of you who know me, know that's NOT the case.

Second, you are absolutely correct about the measurements and it is my intention to post them. But I simply have not had the time to do this. I think that you will find that they cooborate (SP?) the reviews, which should not be discounted entirely and especially not because they were biased.

No worries, no rush for me...I kill as much work time as I possibly can on here
post #32 of 2011
Quote:
Originally Posted by penngray View Post

6" thick bass traps, corner traps? or Big sonotub resonators to attack specific LF?

The walls in my room are supported Contrained Layer Damping panels, so the entire boundary is LF damped. I don't use any "traps" or materials as such. They tend to be too much absorption at HFs.
post #33 of 2011
Quote:
Originally Posted by gedlee View Post

I would not consider this an "alternative" at all. The mains have to be located for imaging and other HF "stuff" and cannot be moved or set for the best bass without compromising the rest of the bandwidth. So uncouple the problem by locating the mains where they need to be and don't worry about trying to take them low - this has huge benefits in power handling and cone excursion. Then distribute subs and use their indivudual freedom of settings (gain, LP and phase) to smooth out the response - augmenting the mains if you will. In my system the mains do go down to about 50-60 Hz so they are still active sources at LFs. I just don't try and push them down to the lowest frequencies, let the subs do that.



While that is your opinion, a lot of rooms are not dedicated HT rooms and are not large rooms. Most people can not place their speakers in the "perfect" place in their room. Three subwoofers located at different places in the room may simply be out of the question for a lot of people. Main speakers placed out in the room may also be out of the question.

While you mains may go down to 50 - 60 Hz, that does not mean much at all to me. So do a lot of speakers at lower SPL levels. My particular "large" R & L main speakers are three way speakers that have integrated subwoofers in them. They do run out of gas at about 45 Hz as measured in room. When the ULF subwoofer is crossed and properly integrated with the main speakers (gain, LP, polarity, adjustable phase, distance setting, correct BM), the end results are quite good.
post #34 of 2011
Hi Earl. Your bass solution is what I would actually consider a one sub solution, that sub being the one you call "Ultra Low Frequency", 25-50hz. The 50-150hz range is solidly the mid-bass radiator range, not what many of us consider to be true subs.

The important thnig is that it apparently works very well. I'm sure your setup lacks nothing in the "slam" area.
post #35 of 2011
Quote:


While that is your opinion, a lot of rooms are not dedicated HT rooms and are not large rooms. Most people can not place their speakers in the "perfect" place in their room. Three subwoofers located at different places in the room may simply be out of the question for a lot of people. Main speakers placed out in the room may also be out of the question.

Good point, that is why I think this thread is more about the "perfect" Sub solution and they are going to ignore the compromises we all have.
post #36 of 2011
Quote:


The walls in my room are supported Contrained Layer Damping panels, so the entire boundary is LF damped. I don't use any "traps" or materials as such. They tend to be too much absorption at HFs.

what LF are you talking about even under 100Hz is controlled? Thats a pretty big wavelength too absorb and I was not able to do it in my room so Im very interested in the design.
post #37 of 2011
Quote:
Originally Posted by J_Palmer_Cass View Post

While that is your opinion, a lot of rooms are not dedicated HT rooms and are not large rooms. Most people can not place their speakers in the "perfect" place in their room. Three subwoofers located at different places in the room may simply be out of the question for a lot of people. Main speakers placed out in the room may also be out of the question.


Its all a matter of priorities so if the right way to do things is beyond what you are willing to do then that's fine, don't do it. But then don't expect the best bass possible.
post #38 of 2011
Quote:
Originally Posted by penngray View Post

People posting "Best they heard" without proof is meaningless because of obvious BIAS during the experience.

The only way to confirm if its good is to post the measurements!

You beat me to it...exactly!

You subjective listening experience is simply that...subjective. You're influenced by all kinds of things.

Without objective measurements..it is meaningless.

His room is heavily treated as he has stated in this thread...much more likely to be influencing the "sound" of the room...rather than the multiple small subs.
post #39 of 2011
Quote:
Originally Posted by mojomike View Post

Hi Earl. Your bass solution is what I would actually consider a one sub solution, that sub being the one you call "Ultra Low Frequency", 25-50hz. The 50-150hz range is solidly the mid-bass radiator range, not what many of us consider to be true subs.

The important thnig is that it apparently works very well. I'm sure your setup lacks nothing in the "slam" area.

This is not at all my definition. To me anything below the Schroeder Frequency, i.e. the modal region, is LF or bass. So this takes us well up into the 100-200 Hz range in a typical home listening room. But you might be correct that "bass" is not a good word (its actually a musical term) and I should use LF, where by this I mean anything "modal".
post #40 of 2011
Quote:
Originally Posted by penngray View Post

I 100% agree, I never understood why people are so attached to full range mains....80Hz or higher is great for mains and let a sub system handled the LF properly.

Im a huge fan of multiple subs for this reason....multi-sub placement can solve things even EQs can't.




It is simple. Properly selected "large" mains can easily they can play down to the 40 to 50 Hz and they do not take up much room. Crossed over to the ULF subwoofer at 50 Hz, you still get stereo bass from the mains if it is on the recording. HSU also recommends crossing to the ULF subwoofer in the 50 Hz area.

Large mains also look slick, and do not require speaker stands!
LL
post #41 of 2011
Quote:
Originally Posted by Johnsteph10 View Post

Without objective measurements..it is meaningless.


I addressed this already, but "meaningless" is a bit extreme. Lots of people have done multiple subs and as far as I know all have found it an improvement. Does the LF absorption in my room affect my results - absolutely - is this the dominate factor - absolutely not.
post #42 of 2011
Quote:
Originally Posted by gedlee View Post

Its all a matter of priorities so if the right way to do things is beyond what you are willing to do then that's fine, don't do it. But then don't expect the best bass possible.




There is more than one way to skin a cat!
post #43 of 2011
I am currently running two subs by simply using a splitter at the back of the preamp. What is the most effective method for connecting more than that? My subs are co-located now for output. I have heard about daisy chaining but not real familiar with it. Would this be a better solution for co-located subs?
post #44 of 2011
Quote:


Its all a matter of priorities so if the right way to do things is beyond what you are willing to do then that's fine, don't do it. But then don't expect the best bass possible.

You have to agree that "Best" has a wide and vary range of meaning. Someone's best is another man's nightmare
post #45 of 2011
Quote:


It is simple. Properly selected "large" mains can easily they can play down to the 40 to 50 Hz and they do not take up much room. Crossed over to the ULF subwoofer at 50 Hz, you still get stereo bass from the mains if it is on the recording. HSU also recommends crossing to the ULF subwoofer in the 50 Hz area.

I just like subs handling anything under 80Hz because I have not found mains to that give me enough punch in that area and if the mains have less then a 10" driver Im not intersted

btw, 50Hz is an interesting recommended crossover from HSU. I have done some crude localization testing with my smaller sealed subs (they have wheels ) and I can locate the sub in the room when playing frequencies in the high 60Hz range...so the idea that 80Hz and under is NOT localized is not true for me.
post #46 of 2011
Thread Starter 
Quote:
Originally Posted by J_Palmer_Cass View Post

There is more than one way to skin a cat!

Well as a cat lover, I resent that....but the thread title is about using a really expensive knife or using several cheap knives.
post #47 of 2011
Quote:
Originally Posted by gedlee View Post

I addressed this already, but "meaningless" is a bit extreme. Lots of people have done multiple subs and as far as I know all have found it an improvement. Does the LF absorption in my room affect my results - absolutely - is this the dominate factor - absolutely not.

Ok, "meaningless" might have been a little extreme.

I'm all for advocating multiple subs (as I've done that in the past and am doing it again with my in-progress build).

I'm questioning the advocacy of multiple small subs being superior to a larger sub without objective measurements. There are too many confounding variables to make such a claim without, at least, an EQ (room treatments being a huge one, for instance).
post #48 of 2011
Thread Starter 
Quote:
Originally Posted by Johnsteph10 View Post

You beat me to it...exactly!

You subjective listening experience is simply that...subjective. You're influenced by all kinds of things.

Without objective measurements..it is meaningless.

His room is heavily treated as he has stated in this thread...much more likely to be influencing the "sound" of the room...rather than the multiple small subs.

I would point you to the link showing Markus's measurements using the technique. But for now, let's assume that the Earl's room sounds great and focus on whether it is the best technique or use of resources (as in $) or if alternative methods work as well or better.
post #49 of 2011
Hi Earl! How do you time align three 50-150hz subs with each other and with your mains? And even if they are time aligned it would only be for a single position in the room, right?
post #50 of 2011
Quote:
Originally Posted by penngray View Post

You have to agree that "Best" has a wide and vary range of meaning. Someone's best is another man's nightmare

That is not even half way funny. People know when they have heard the best.

For me, it happened quite a few years ago in the home of an employee of Dolby Labs.

The system used a 200 watts X 2 Dynaco solid state amp, Dynaco pre-amp, B&O turntable and most surprisingly, a pair of 3 way bookshelf speakers with 12 inch woofers, from a small company that had already discontinued them. The sound quality was far better than anything I had ever heard in a high end shop or anyones home.

The sense of having the band in the room was uncanny. The space around each instrument, including the space behind each instrument was palpable.
The precise front to back, hight and the left to right panorama were just awesome.

There was no subwoofer and with anything the owner played, the bass was ample.

Not sure if what I heard is anything like what Geddes calls "spatial", but the overall sense or realism of the sytem I heard has never been topped.

Working at Dolby Labs may have had something to do with that dude getting his system set up so well.
post #51 of 2011
Quote:


That is not even half way funny. People know when they have heard the best.


You took my statement the wrong way, don't be so serious about it

Your best is not my best because 'best' is a very, very subjective and almost meaningless term in my books.

Lets just say if you have speakers/subs on the floor in a room and I can see them then I do not think you have a great setup. Again, that is my definition of 'best', you can define it as you will.
post #52 of 2011
Quote:
Originally Posted by penngray View Post

You have to agree that "Best" has a wide and vary range of meaning. Someone's best is another man's nightmare


Lets consider "best" here to be quantitative to get away from the subjective. The sound field in a room at LF is highly variable in space and in frequency. "Best" then means the smoothest in both of those aspects. I don't think that anyone could effectively argue that a highly resonant spatially variable bass is what we want, and if they did then this is not the place to be since the underlying assumption in all that's said here is that smoothness is king.
post #53 of 2011
Quote:


Lets consider "best" here to be quantitative to get away from the subjective.

That was my point above

I agree and does that mean "best" is defined as best FR plot/Waterfall/spatial/etc alone or do we add best SPL/low distortion capabilities too?
post #54 of 2011
Quote:
Originally Posted by Johnsteph10 View Post

I'm questioning the advocacy of multiple small subs being superior to a larger sub without objective measurements. There are too many confounding variables to make such a claim without, at least, an EQ (room treatments being a huge one, for instance).

As I said, I've done a lot of rooms this way and have a lot of measurements, I just lack the time to display them. But there is an abundance of articles, papers and simulations (one on my website I believe) which show that multiple subs will yield the "best" response in an objective sense. On this point there can be no argument - everyone who has studied the situation agrees that multiple subs spatially located achieves the best overall response.

We all disagree on the details - where to put them, how to set them up, etc. - but no one disagrees on the premis that you need more than one. JBL would like to sell lots of expensive subs and a very expensive magic box. I don;t feel that is necessary - I have no doubt that the results will be great, only that its not the most cost effective solution. I like cost effective.
post #55 of 2011
Quote:
Originally Posted by steve71 View Post

Hi Earl! How do you time align three 50-150hz subs with each other and with your mains? And even if they are time aligned it would only be for a single position in the room, right?


I don't think that time alignment at LF has any significance. At 50 Hz. it takes almost 40-50 ms. for the brain to even register that a tone at this frequency is present. What kind of sensitivity could a hearing system have to a few ms time alignment at those frequencies.
post #56 of 2011
Quote:


I have no doubt that the results will be great, only that its not the most cost effective solution. I like cost effective.

Room size and listening requirements would matter too wouldn't they?
I have a hard time your thinking 4 subs defined as "plate amps about $100 and the B&C woofer about $150 " come close to my TC2K drivers (2 sealed, 2 ported) with 1000W into them each or in my other room 4 Q18s in an IB array driven by a FACE F1200TS amp or others have 4 18" Mal-x drivers in sealed enclosures driven by insane Watts.

If we want to get right down to the best sound and not worry about the big world of compromise then you have realize that who nature of an IB design is to produce the best sound possible. (many sealed subs together equates to an IB but you need big enclosures).
post #57 of 2011
Quote:
Originally Posted by penngray View Post

That was my point above

I agree and does that mean "best" is defined as best FR plot/Waterfall/spatial/etc alone or do we add best SPL/low distortion capabilities too?

The use of waterfalls at these frequencies is controversial and I tend to agree that they are not that meaningful - they don't really show anything that a spatial and spectral plot doesn't show. Spectral data and spatial variance is the key.

Max SPL is a matter of choice, so let's discount that. THD at LF and over the very limited bandwidth of a sub is not a significant issue either. But I will say that I use bandpass subs which LP filter any distortion and I have found this to help with NOT localizing the subs. But I would not consider nonlinearity to be a significant issue.
post #58 of 2011
Quote:


The use of waterfalls at these frequencies is controversial and I tend to agree that they are not that meaningful - they don't really show anything that a spatial and spectral plot doesn't show. Spectral data and spatial variance is the key.

very true, although they help me understand it the "time decay" stuff better.
post #59 of 2011
Quote:
Originally Posted by penngray View Post

Room size and listening requirements would matter too wouldn't they?
I have a hard time your thinking 4 subs defined as "plate amps about $100 and the B&C woofer about $150 " come close to my TC2K drivers (2 sealed, 2 ported) with 1000W into them each or in my other room 4 Q18s in an IB array driven by a FACE F1200TS amp or others have 4 18" Mal-x drivers in sealed enclosures driven by insane Watts.

My room is "sufficient" to cause pain - thats enough for me thanks. But remember, I have a completely sealed fairly small room so yes this does dramatically lower the power requirements over a leaky or much larger room. Lets not play the "watts" game OK, a lot depends on efficiency.
post #60 of 2011
Quote:


My room is "sufficient" to cause pain - thats enough for me thanks. But remember, I have a completely sealed fairly small room so yes this does dramatically lower the power requirements over a leaky or much larger room. Lets not play the "watts" game OK, a lot depends on efficiency.

Im not trying to game the debate, your post on the first page using that amp/driver example suggests that its a solution for any of us but in reality from what I read is that it only works great in your room because your room and treatments improve it to the Nth degree.

Would it be fair to say that your room has a HUGE impact on the performance of your "cheap solution"?

My custom HT room is not that large (13x25x8), I have treated walls (with masking to reflect HIGH frequencies) and corner tri-traps that handle Frequences down to around 100Hz very well (under that needs special resonators,etc which I have not built) so based on what you are saying I could build 4 sealed subs with that amp/driver choice and I should be very happy and it should be as good as my current 4 TC2K 15" subs?
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