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

No worries, no rush for me...I kill as much work time as I possibly can on here

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.

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.

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.

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.

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.

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 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.

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".

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!

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.

There is more than one way to skin a cat!

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?

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

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.

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).

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?

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.

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.

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.

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?

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.

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.

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).

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.

very true, although they help me understand it the "time decay" stuff better.

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?