Genesis Advanced Technologies SuperSub Subwoofer

[Blackmorec]

In terms of bass reproduction, you may find this article about bass correction an interesting read:

http://www.theabsolutesound.com/art...devialet-expert-220-pro-integrated-amplifier/

In some of my recent posts I’ve made observations that my system is now able to reproduce the entire venue space before any note is played. I observed that the mismatch between what my ears hear and my eyes see is now so profound its actually disorientating and I need to listen in semi darkness with my eyes closed (obviously depending on the recording).

And this is with 2 way Magico S1MkIIs with Devialet 440 and SAM set to 100%. According to Devialet’s measurements, the S1 with SAM will reproduce notes down to 17Hz. Hard to believe but listen to Dorian’s recording of Jean Guillou playing Mussorgsky’s Pictures at an Exhibition on the Zurich Tonhalle‘s Great Organ and your opinion may change. A symphony orchestra has a huge presence before bows meet strings or lips caress reeds or mouthpieces. Chairs creek, large instruments rumble, bows gently tap wooden bodies, clothes rustle and the ambience is huge, voluminous and full of anticipation.

Press play and as the track starts the room disappears and you are transported into the recording venue, which may be a small intimate studio or the vast concert hall I described. The music then happens within that venue.

My room is small, symmetrical, reflective and lossy in the bass with large areas of diffusion and I listen near-field with speakers well away from walls, very accurately matched positionally and toed in to about 1-2 feet behind the listener’s ears.

Switch off SAM and the illusion of a venue disappears

I’m not delusional in trying to say that my system sounds anything like something with an array of 18” servo woofers. Its a 2-way system with 7” woofers In a very small room. What I am saying is that maybe huge woofer area is one, but not the only way to create the presence of a large venue sans music and that the SAM algorithms seem to be able to pull off the same trick, albeit in a very different way, at the polar opposite end of woofer/sub-woofer design

 

[LL21]

IF you want to try overlapping the subs and mains, the phase control on your subwoofer amp can help. When the outputs of subs and mains are combining with a large amount of phase difference between them, you won't get the "peaking" that you would if they overlapped AND combined approximately in-phase.

As a supplemental or alternative technique, you might try plugging the port(s) of the mains, and/or filling the ports with open-cell foam. The net result in either case will be less bottom-end output from the mains. Plugging the ports will better protect against over-excursion, while the open-cell foam may tend to sound better once you have "dialed in" the proper amount of foam for your application. I'd try reticulated foam with about 30 pores per inch, and adjust the thickness of the "foam plug" in the port. I can't predict how much you might need - too many variables (woofer parameters & boundary reinforcement & the subwoofer's low-pass filter frequency and slope being among them).

Imo as long as your mains don't really need protection from bass excursions, you may well be better off WITHOUT a highpass filter in their signal path.

The ear is much more sensitive to frequency response peaks than it is to phase anomalies in the bass region, so focus on getting smooth in-room frequency response and you will be solving the problem that matters most. Don't let your sensibilities be offended by what looks like phase anomalies "on paper". It is not a bad thing to have multiple sources contributing in the same frequency region at low frequencies, from a room-interaction standpoint. And room interaction generally plays a very large role in the bass region.

In my opinion.

Thank you again! Very very interesting. You are suggesting running the Wilsons full-range?

 

[DonH50]

Interesting stuff. Nice job, Gary! There have been other woofer/sub systems using different drivers and they are always a pain to integrate. You are one dedicated guy!

General comments, just IME/IMO:

If your main speakers are ported, you generally want to cross over to your sub well above their port tuning frequency, to reduce distortion and avoid the phase issues around and below the port tuning frequency as others said earlier.

One other factor in sub placement and crossover is the room itself. Room modes, from sound waves bouncing off one wall (or floor/ceiling), can cause significant (~6 dB or more) peaks and deep (~30 dB or more depending on the room) nulls that are fairly narrow and centered at frequencies depending upon your room's dimensions. Peaks you can usually EQ away, but true nulls are tougher and not amenable to EQ. Since they arise from signals cancelling one another, simply amplifying that frequency does not help since (e.g.) 1-1 = 0, and if you amplify the signal then 10-10 is still 0.

The usual practical solutions are to move the listening position out of the null, and/or arrange the subs and perhaps other speakers to "cancel" the null with an active driver. So where you place the subs, mains, and listening position; and, where (at what frequency) you set the crossover and how you adjust the delay/phase of the signals to mains and sub(s), is all critical for achieving the best sound. That is partly why guys like Gary spend a LOT of time working to properly set up and integrate a complete system in your room. Or their room.

HTH - Don

 

[musicfirst1]

In terms of bass reproduction, you may find this article about bass correction an interesting read:

http://www.theabsolutesound.com/art...devialet-expert-220-pro-integrated-amplifier/

In some of my recent posts I’ve made observations that my system is now able to reproduce the entire venue space before any note is played. I observed that the mismatch between what my ears hear and my eyes see is now so profound its actually disorientating and I need to listen in semi darkness with my eyes closed (obviously depending on the recording).

And this is with 2 way Magico S1MkIIs with Devialet 440 and SAM set to 100%. According to Devialet’s measurements, the S1 with SAM will reproduce notes down to 17Hz. Hard to believe but listen to Dorian’s recording of Jean Guillou playing Mussorgsky’s Pictures at an Exhibition on the Zurich Tonhalle‘s Great Organ and your opinion may change. A symphony orchestra has a huge presence before bows meet strings or lips caress reeds or mouthpieces. Chairs creek, large instruments rumble, bows gently tap wooden bodies, clothes rustle and the ambience is huge, voluminous and full of anticipation.

Press play and as the track starts the room disappears and you are transported into the recording venue, which may be a small intimate studio or the vast concert hall I described. The music then happens within that venue.

My room is small, symmetrical, reflective and lossy in the bass with large areas of diffusion and I listen near-field with speakers well away from walls, very accurately matched positionally and toed in to about 1-2 feet behind the listener’s ears.

Switch off SAM and the illusion of a venue disappears

I’m not delusional in trying to say that my system sounds anything like something with an array of 18” servo woofers. Its a 2-way system with 7” woofers In a very small room. What I am saying is that maybe huge woofer area is one, but not the only way to create the presence of a large venue sans music and that the SAM algorithms seem to be able to pull off the same trick, albeit in a very different way, at the polar opposite end of woofer/sub-woofer design

Interesting observations. Having owned both the SAM'd Devialets with the Jamo R909s (two 15" drivers per channel) and subsequently the REL 6 pack with main speakers running full range, respectfully the SAM'd Jamos only hint at what the latter can achieve. I suspect that it has to do with the relative surface area of the low frequency drivers, as Gary and others have speculated here.

 

[Blackmorec]

Hi musicfirst 100,
I have no doubt whatsoever that you’re never going to get the same results from SAM’d Jamo R909s vs a REL 6 pack or some of the Subwoofers discussed here in this tread. But I thought it was interesting that the most significant and groundbreaking result of the Genesis SuperSub, namely the ability to creat a supersized concert hall ambience whose size could be ‘sensed’ even before the music started could also be reproduced by 2 7’ woofers whose output was extended and phase linearised down to 17Hz.
Interestingly I only got these ‘venue creation’ results after much work to optimise my network supply stream, but after that work was complete I reported that my system had developed the ability to reproduce the acoustics and feel of a large concert venue even before a single note of music was played, to the degree that the aural and visaul sensory inputs were so conflicted as to be disorientating.
One of my previous systems was based on Avantgarde Trio horns with 4 subwoofers, while a friend had a 5 speaker Trio/Uno based system with 7 subs and while it had TREMENDOUS slam, ease, and fidelity in the bass, it did not reproduce the venue acoustics in the same way that‘s being reported here. Is the venue creation sans music something you hear with the RELs?

 

[LL21]

...
Interestingly I only got these ‘venue creation’ results after much work to optimise my network supply stream, but after that work was complete I reported that my system had developed the ability to reproduce the acoustics and feel of a large concert venue even before a single note of music was played, to the degree that the aural and visaul sensory inputs were so conflicted as to be disorientating.

That is EXACTLY the description...before a single note is even played. And as soon as you hit 'Pause', it all disappears and you are INSTANTLY transported back into this world having left Narnia...

 

[DaveC]

However, during my experiments, I found that with exactly the same cone surface area, and the same excursion, 8/12/15 inch cones all sound different. Or feel different. Hence, in the SuperSub I used all three sizes.

Agreed.

My theory on the difference in sound between driver sizes, while keeping surface area/excursion the same, has to do with mechanical impedance.

The setup with multiple smaller drivers is going to have much more circumference. For two 18" drivers you get 2(pi * 18) = 113.1 For eight 9" drivers you get 8(pi * 9) = 226.2

So while area is close to the same the circumference is doubled. In this region the driver is losing efficiency and there are likely some audible effects that are created as a result. Anyways, just a theory... I do agree that different sized drivers sound different but the reasons why don't seem that obvious.

 

[musicfirst1]

Hi musicfirst 100,

One of my previous systems was based on Avantgarde Trio horns with 4 subwoofers, while a friend had a 5 speaker Trio/Uno based system with 7 subs and while it had TREMENDOUS slam, ease, and fidelity in the bass, it did not reproduce the venue acoustics in the same way that‘s being reported here. Is the venue creation sans music something you hear with the RELs?

ABSOLUTELY! I first heard this virtual reality effect at a show featuring the REL 6 pack with a pair of Rockport speakers. I immediately sold my soul to buy a pair of full range Rockport Cygnus and a REL Gibraltar G1 '6 pack'.

Even though the Cygnus has two 10" drivers and once set up correctly, do well down to 20Hz by themselves, the addition of the Six 12" drivers of the RELs resulted, once dialed in, in in a different level of the 'acoustic without music' effect. My room is 13.5 ft wide, but open concept to 45 feet long, so I'm sure the Rels contribution was larger than what it might otherwise have been.

The 'insane ambiance' is what I'm addicted to now, the lead-in for live music venues being very telling. As a matter of fact, I have heard the eves surrounding the roof outside my home rattle when standing outside and playing loops of hall ambiance on some classical recordings. This effect can be heard at realistic playback levels with peaks less than 100db.

The interesting thing is this effect is indeed disconcerting and even disorienting with almost a pressure suck out when the recording stops..

I'd love to add a pair of 15s or 18s to the REL stack, but integrating subs is possibly the most difficult of setup arts.

FYI my measured in-room system response is -3db @ 15 Hz, but as Gary and others have said here, the measured response only tells part of the story.

People who write off subs, I would venture have never heard them correctly integrated let alone being able to reproduce the 'sound of silence' described in this thread...

Its good to find others that 'believe' in this as an absolute necessity for fidelity to the source.

 

[DonH50]

Back in the 1980's (and well before and after I am sure) there was a lot of focus on using multiple smaller drivers in place of fewer, larger drivers. Never seemed to work out all that well. I tend to think @DaveC is on to something with the surrounds but there is more to it than that, at least IME. Usual disclaimer: I am NOT a speaker designer, and my piddling with such was long ago.

Long ago (but in this galaxy) I tried building a subwoofer from a large array of smaller (4" IIRC) drivers. I noticed several things that led to its downfall, and ultimately my design became a single 12" driver with servo control (using a second voice coil ala. Infinity back then, Rythmik and others now -- not sure what Gary uses). Here are a few things I remember from long ago:

1. People tend to focus on area and forget about excursion. So did I. The argument is that a bunch of little drivers do not need as much excursion. Now, you need nine (9) little 4" driver to equal the surface area of a single 12" cone. So I used 12 for margin. The problem is, if I used exactly 9 x 4" drivers, I have the area covered, but to move the same amount of air as my 12" driver, the linear displacement of each 4" driver must match that of the 12" driver. Oops. Let's see, the 12" driver had about 3", each 4" about 1/2", nope, not gonna' end well. It didn't. Need a LOT more drivers.
2. The low-frequency cutoff off a driver is related to its mass, among other things, so to equal the roughly 16 Hz low end of my 12" driver, I could either mass-load the 4" cones (yes, tried that, messy and burned up a few drivers trying to push that much mass) or EQ the heck out of them. EQ works, see the EQ for a Bose 901, but requires a big LF boost (ditto), leading to greater excursion and higher distortion to move the same amount of air... Oops again. Tail-chasing subwoofers.
3. One of the drivers for these multi-driver monsters was "speed". That led to a bunch of work to see why "speed" mattered for a subwoofer. I mean, if you are rolling off at 60~80 Hz, what sort of bandwidth did a sub really need? What we (I and many bemused cohorts from my pool of college professors, audio and band buddies, etc.) discovered was the "speed" that mattered was really how fast the driver stopped and to a lesser extent started (attack and decay). The thing that seemed to matter the most was having a driver that "stopped" quickly instead of "winding down" with ringing tails that muddied the bass. The gross analogy would be turning a tight kick drum or tom into a booming kettle drum. Controlling a single small driver was easier, but by the time you got enough of them all wired up, the overall problem of driver-plus-amp was not all that different. The array of small drivers "won", but at great cost.
4. Actually constructing, wiring, and driving the array turned out to be complicated. I started with a single passive crossover driven by a decent amplifier (Levinson or Krell, forget after all this time) but a combination of impedance and control that made sense just was not really realizable. At least by me; smarter real speaker designers probably could have done it. Too many series connections made it easier to drive but lost control so the decay was not fast enough. More in parallel provided better sound but by then I was looking at 1-2 ohm load and didn't really want to compete with Apogee for who could blow up the most amplifiers.
5. Getting a matched set of drivers wasn't easy. They were pretty close off-the-shelf, but minor variances meant some measuring to make sure load-sharing among them was reasonable.
6. Making a cabinet with a stiff, well-braced mounting panel is much harder with a bunch of little holes all over it than one or two bigger ones. Mechanical integrity came into play more than I expected in terms of "buzzy" vibrations (solvable) and flexure across the mounting baffle (also solvable but a lot more work -- and weight). And as noted earlier, you need enough space between drivers for mounting and bracing, plus each driver has its own surround and mounting ring, so the overall box got much, much bigger.
7. For reasons I never figured out at the time, but having to do with the acoustics of the launched wavefront (took another grad class to be able to actually calculate and understand it, and don't ask me now), the array and single larger driver never sounded the same. Some time later I was able to make some measurements of distortion and impulse response and found sure enough distortion was much higher, which means more audible since the harmonics of a sub are much easier to hear than the fundamental (see Fletcher-Munson), the the impulse or step response was not as clean since all the little drivers did not quite align completely in time.

I had a few other thoughts but they slipped away whilst writing this novel and it's time for lunch. Bottom line is that, while an array seemed like such a nice idea at the time, in practice it simply did not work. Bigger, worse performance, harder to drive, what's not to like? But it looked impressive!

I did toy with using a 12" and 8" driver in my sub but that is another tale. That actually worked a lot better, but took much longer to "dial in" than I ever expected, with a very complex electronic (no DSP then) crossover with some special circuits to help with phase/time alignment and to blend the drivers. In the end I built a nice little 12" servo-sub that served me well for many years. One driver, one crossover/servo control box, and much loss hair loss in the design and integration with my mains (Maggies).

FWIWFM - Don

 

[garylkoh]

Gary,

Amazing. You are busy opening up the new place and finding the time to help us audio kinder with our extravagances! Thank you! This is incredibly helpful and I will be sure to continue to pursue. Best wishes with the re-opening.

I will always try to help fellow music lovers.

I am glad that this topic has generated so much interest, and also from people who are much more knowledgeable than me!

 

[garylkoh]

Imo as long as your mains don't really need protection from bass excursions, you may well be better off WITHOUT a highpass filter in their signal path.

The ear is much more sensitive to frequency response peaks than it is to phase anomalies in the bass region, so focus on getting smooth in-room frequency response and you will be solving the problem that matters most. Don't let your sensibilities be offended by what looks like phase anomalies "on paper". It is not a bad thing to have multiple sources contributing in the same frequency region at low frequencies, from a room-interaction standpoint. And room interaction generally plays a very large role in the bass region.

In my opinion.

I agree.

I have very little experience with ported loudspeakers, so I will defer to the more knowledgeable members here.

 

[garylkoh]

Agreed.

My theory on the difference in sound between driver sizes, while keeping surface area/excursion the same, has to do with mechanical impedance.

The setup with multiple smaller drivers is going to have much more circumference. For two 18" drivers you get 2(pi * 18) = 113.1 For eight 9" drivers you get 8(pi * 9) = 226.2

So while area is close to the same the circumference is doubled. In this region the driver is losing efficiency and there are likely some audible effects that are created as a result. Anyways, just a theory... I do agree that different sized drivers sound different but the reasons why don't seem that obvious.

That is also one of the theories that I was exploring. The circumference is where air turbulence could also occur as the cone drives the air. Bud Purvine has a patented technology eNAble that improves the air/cone interface, and this could be an area where more experimentation can occur.

Another theory is that the larger cones are also deeper, and the "contained air" within the cone improves the interface between the cone and hence better drives the air.

But these and other theories are still speculation at this point. I know what I hear though..... just don't know how to even approach measuring it.

 

[DaveC]

That is also one of the theories that I was exploring. The circumference is where air turbulence could also occur as the cone drives the air. Bud Purvine has a patented technology eNAble that improves the air/cone interface, and this could be an area where more experimentation can occur.

Another theory is that the larger cones are also deeper, and the "contained air" within the cone improves the interface between the cone and hence better drives the air.

But these and other theories are still speculation at this point. I know what I hear though..... just don't know how to even approach measuring it.

I paid Bud to make an enabl design for the midrange drivers on my speaker. The issue I was having was the cone is made of lightweight paper, and would get that "shout" at higher SPLs that was unacceptable, the main goal of the speaker is to remove as much of the compromise of a single driver while maintaining that magic that some of the best single drivers provide, so getting rid of shout was important to me. Enabl accomplished that, it got rid of the distortions that become audible as the SPL increases so you can play at high SPLs without distortions that give away the speaker is playing at high SPL. It also makes for a general improvement in sound quality be removing distortions at any SPL, however I can't see how it can improve mechanical impedance or the turbulence around the perimeter of the driver cone... but IDK, I'm certainly open to the possibility.

 

[garylkoh]

Thanks, DonH50 for chiming in. As usual, you bring technical perspective.

Back in the 1980's (and well before and after I am sure) there was a lot of focus on using multiple smaller drivers in place of fewer, larger drivers. Never seemed to work out all that well. I tend to think @DaveC is on to something with the surrounds but there is more to it than that, at least IME. Usual disclaimer: I am NOT a speaker designer, and my piddling with such was long ago.

Long ago (but in this galaxy) I tried building a subwoofer from a large array of smaller (4" IIRC) drivers. I noticed several things that led to its downfall, and ultimately my design became a single 12" driver with servo control (using a second voice coil ala. Infinity back then, Rythmik and others now -- not sure what Gary uses). Here are a few things I remember from long ago:

I use a piezoelectric sensor as an accelerometer.

Bottom line is that, while an array seemed like such a nice idea at the time, in practice it simply did not work. Bigger, worse performance, harder to drive, what's not to like? But it looked impressive!

IMHO, the biggest factor in my experience has been that the one thing that never seemed to be mentioned has been component precision and tolerance. We give much more importance to expensive. An array of inexpensive drivers is going to be really badly matched, and I am pretty sure that you will find the impulse response to be a mess. On the other hand, if you had say 100-200 of these drivers and find the 16 best-matched ones and throw away the rest, I would bet that you could get an impulse response to match one single larger driver.

To get the SuperSub to work, I had to match the whole servo-feedback loop - with everything inside the loop....... I think that you can imagine.

I did toy with using a 12" and 8" driver in my sub but that is another tale. That actually worked a lot better, but took much longer to "dial in" than I ever expected, with a very complex electronic (no DSP then) crossover with some special circuits to help with phase/time alignment and to blend the drivers. In the end I built a nice little 12" servo-sub that served me well for many years. One driver, one crossover/servo control box, and much loss hair loss in the design and integration with my mains (Maggies).

FWIWFM - Don

I think you need to resurrect that, Don. And add a 15" driver to the mix. I think that it would be awesome with Maggies.

 

[DonH50]

Thanks, DonH50 for chiming in. As usual, you bring technical perspective.

Thanks, it's what I do, though unpopular here. I do know enough to have an inkling of the effort you put into this beast!

I use a piezoelectric sensor as an accelerometer.

That's what Velodyne and a couple of others used. I debated the pros and cons; can be utilized to better monitor for breakup, but voice coil sensing does better compensating thermal effects and back then was cheaper and wider bandwidth -- once you had a dual voice-coil driver, not all that common then. I had one, and at the time better understood that approach, so jumped the other way.

IMHO, the biggest factor in my experience has been that the one thing that never seemed to be mentioned has been component precision and tolerance. We give much more importance to expensive. An array of inexpensive drivers is going to be really badly matched, and I am pretty sure that you will find the impulse response to be a mess. On the other hand, if you had say 100-200 of these drivers and find the 16 best-matched ones and throw away the rest, I would bet that you could get an impulse response to match one single larger driver.

Yes, you nailed it, and I mentioned that in my later post. The idea that you can use a bunch of cheap (and thus mismatched) drivers was quickly disabused. Trying to load-balance was really impractical unless I went with a bunch of amps (not such a big deal now with class D and DSP, but impractical back then) and the impulse response sucked (can I say that here?)

To get the SuperSub to work, I had to match the whole servo-feedback loop - with everything inside the loop....... I think that you can imagine.

Yes, even with a single driver it took some tinkering, and the effort you must have put into making such a complex system (for a subwoofer) work is mind-boggling.

I think you need to resurrect that, Don. And add a 15" driver to the mix. I think that it would be awesome with Maggies.

Probably, but my time is extremely limited these days, and some time back I found a kindred soul in subwoofer design with a similar day job in Brian at Rythmik so went a different route. If I ever retire I have a long, long list of things I'd love to get back into -- audio, photography, woodworking... I have a bunch of toys, some still in their wrappers, longing to be used.

Until then, I appreciate your posting here so I (and others) can live vicariously through your experiences -- without the solder fumes!

Thanks for all you do, Gary - Don

 

[garylkoh]

I'd love to add a pair of 15s or 18s to the REL stack, but integrating subs is possibly the most difficult of setup arts.


People who write off subs, I would venture have never heard them correctly integrated let alone being able to reproduce the 'sound of silence' described in this thread...

Amen to that!

 

[dbastin]

Hi,
I'm hoping to resurrect this interesting thread. I am curious about @garylkoh view on a few things, but all comments are welcome.

I am not an engineer or speaker designer, but a curious audiophile.

Why is the SuperSub squat rather than a taller line array tower?
Why are the drivers firing sideways rather than forward and backwards?
Are there sonic advantages to subs in horizontally opposed configuration compared to push-push?
Did you consider mounting the SuperSub off the floor away from the node of the floor to ceiling mode?
Why did you not opt for 2 or 3 way subs? I suspect you'll say the crossovers are detrimental.
How did you ensure each driver moves the exact same amount of air? Reduce the outputs of the 12 and 15 inch drivers to match the 8 inch in terms of air movement?

Thanks

 

[sbo6]

One other factor in sub placement and crossover is the room itself. Room modes, from sound waves bouncing off one wall (or floor/ceiling), can cause significant (~6 dB or more) peaks and deep (~30 dB or more depending on the room) nulls that are fairly narrow and centered at frequencies depending upon your room's dimensions. Peaks you can usually EQ away, but true nulls are tougher and not amenable to EQ. Since they arise from signals cancelling one another, simply amplifying that frequency does not help since (e.g.) 1-1 = 0, and if you amplify the signal then 10-10 is still 0.

The usual practical solutions are to move the listening position out of the null, and/or arrange the subs and perhaps other speakers to "cancel" the null with an active driver. So where you place the subs, mains, and listening position; and, where (at what frequency) you set the crossover and how you adjust the delay/phase of the signals to mains and sub(s), is all critical for achieving the best sound. That is partly why guys like Gary spend a LOT of time working to properly set up and integrate a complete system in your room. Or their room.

HTH - Don

And this is why most folks that buy and set up their sub(s) say the subs sounded terrible, yielded slow and tubby bass. Because it takes more than a few hours to properly integrate subs. I have hundreds of measurements and have had subs in every location in my room, raised and lowered to achieve what I believe is exceptional bass. Two subs are good, four integrated well (no easy task) takes it to great. I've heard few rooms / audio stores with subs integrated well. At that's why subs sometimes get a bad wrap.

 

[LL21]

And this is why most folks that buy and set up their sub(s) say the subs sounded terrible, yielded slow and tubby bass. Because it takes more than a few hours to properly integrate subs. I have hundreds of measurements and have had subs in every location in my room, raised and lowered to achieve what I believe is exceptional bass. Two subs are good, four integrated well (no easy task) takes it to great. I've heard few rooms / audio stores with subs integrated well. At that's why subs sometimes get a bad wrap.

Hear hear...at least on integration. I confess, we have not [yet] done the stereo sub thing.

 

[dbastin]

had subs in every location in my room, raised and lowered to achieve what I believe is exceptional bass.

Do you mean raised/lowered output volume, crossover, or off the floor?