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Best bass in Earth! Bass that just smells right...

Bass ,room acoustics, attack, delay, headroom, pressurization, and integration with the main speakers. So this has been my quest. Perfect bass that enhances everything yet detracts from nothing...

Over the 25 plus years as a hobbyist (mostly Audiophile/Music lover) yet also a mechanical engineer and Virgo perfection is a must. Once I heard the swarm/distributed bass array done right I was sold. I probably have spent 10s of thousand over the years buying and selling just bass/subwoofers and every gizmo to aid in this process.

I finally find myself with 26 10 inch woofers (only using 20 at the moment)  from four Kinergetics sw 800's in a small 20 x 16 room. 4 towers with 5 10 inch Seas each and 2 of the smaller subs with 3 10 inch woofers each. They are all in great condition given age the drivers are tight and work perfectly. Of all the money I have spent in home audio this has been my most difficult challenge to achieve perfection. I love Stats and Maggies but also like AC/DC and other music that the plannars are not the best at. Dyna Audio and Dunlavy speakers are the fastest coned sealed speakers (I am sure there are a million speakers out there that equal or better them not here to debate speakers) . I personally have always preferred the sound of FAST sealed cone speakers.

Back to the bottom foundation which I feel all speakers need regardless of price and woofer size. Trying to get four Sub woofers correct in a room is not easy. I probably have 200 hours into these SW 800's and now trying different AMPs and configurations. Im close but not there Id give it 88-91 percent but that last 10 percent is the magic.

So for they peeps out there getting into this can of worms. First unless your a sadomasochist like me it's probably best to buy a system like the Audio Kinesis or Debra system. It's just guaranteed results. Second this is for music not HT there is a difference. Although I had the HSU ULS 15's sealed 2 of em and they are darn good, Revel b 15' A's, Muse Model 18's along with several others. These SW 800's are more like actual speakers that require a lot of work to get right. They also use a funky forward distortion feedback Compusound circuitry (Im not an EE but from what little I was able to read it sounds like a forward servo design in their BSC cross overs) tons of pros and cons to the design but the fact they were meant to mate with the original Martin Logan full panel CLS says volumes when it comes to transparency. Although I dont use the high pass just the low pass.

So if you are into real music and enjoy room pressurization with out destroying (actually increasing, presence, timing, and smell of the music) multiple subwoofers are a mandatory.

I am writing this post for all the peeps getting into real bass so you dont make all the mistakes I have made. We all know how expensive mistakes are that is and why we are members of Agon and other groups. I do want to Thank a couple of members on here for their help and wisdom. I wont name them they know who they are. And special Thank you and Happy New Year to the moderators and founders of Agon for giving all of us a place to gain view points, experiences, and wisdom!

-Allgood
haywood310

Showing 4 responses by audiokinesis

audiokinesis
2,755 posts
 
@brotw posted: " As I understand it, an array of subs would be very effective at smoothing out the bass response of the room over a wider sweet spot. What about spatial cues from bass frequencies? "

The good news is, you can have both.

My understanding is that true stereo below 80 Hz is actually quite rare, but if you want the ability to reproduce it, then (assuming four subs total) send the left channel signal to the two subs located towards the left-hand side of the room, and the right channel signal to the two subs located towards the right-hand side of the room.

If you’d like to synthesize the sort of immersive ambience we might get from true stereo bass, try this: Set the two subs on the left-hand side of the room both 90 degrees apart in phase from the two subs on the right-hand side of the room. So for instance if the two left-hand subs have the phase control set at 30 degrees, the two right-hand subs would have the phase control set at 120 degrees. Credit to David Griesinger (inventor of the Lexicon processor) for this idea; his original suggestion was to use two subs, located along the side walls to the left and right of the listening area. That 90 degrees phase difference isn’t necessarily carved in stone either - you can go beyond 90 degrees, at the expense of increased cancellation at the very bottom end (which in some cases may be desirable).

Duke
(disclaimer, in case the connection isn’t obvious: I make the Swarm)
audiokinesis
2,755 posts
 
@brotw posted: "Do 4+ instead of dual subs shine best in monitor/stat/maggie systems with subs crossed at ~80 HZ?"

I think that’s a fair statement. But I have customers crossing over their Swarms at the minimum 30 Hz setting and finding them to be a worthwhile improvement over one or two subs.

@brotw again: "Decoupling bass frequency from mains allows for smoother room response using multiple subs, but I wonder how anchored in the soundstage 40-80Hz notes from stand up bass would sound."

I use a 4th order lowpass filter so that any subs far away from the mains don’t pass upper bass/lower midrange energy loud enough to give away their locations. To the best of my knowledge this has worked well for crossover frequencies up to 80 Hz. I don’t think there would be any problem with upright bass, especially since the ear will tend to localize the notes based on the overtones rather than the fundamentals.

@phusis posted: " Assuming there is stereo information below 80 Hz, rare it may be, and that one, if placement allowed, would like to take advantage of stereo information here, how would you approach connecting a diagonally positioned pair of subs (just 2, not 4) - like, one sub in the front left corner, and one in the rear right corner? "

I’d send the left channel signal to the left front corner sub, and the right channel signal to the right rear corner sub.

The mono-vs-stereo subwoofers issue is most likely to come up for a system like my Swarm, where all four subs are passive and can be driven by a single amplifier for mono bass, or by two amplifiers (at additional cost) for stereo bass. If you have two (or more) powered subs, imo you might as well connect them in stereo if that’s feasible. 

My understanding that stereo bass is rare is largely based on a conversation with Earl Geddes wherein he described working as a consultant for Ford and the question arose of whether or not to provide stereo low bass for a high-end sound system. So he asked all of the engineers to bring in their CD’s. I don’t recall how many he analyzed, but he did not find a single one with stereo information below either 80 Hz or 100 Hz (my memory is foggy on the exact figure). I think there are audiophile recordings with true stereo bass, seems to me I read about some many years ago, but I didn’t make note of what they were. If anyone reading this knows of any recordings with true stereo south of 80 Hz, I’d be very interested in knowing about them.

Duke
audiokinesis
2,755 posts
 
Brotw wrote: " Seriously, I’d have to play with crossover frequencies for best integration. "

Don’t forget that the phase control on the subs can help with integration. Sometimes overlapping the mains a bit + putting the subs somewhat out-of-phase with the mains gives the best results.

"...thankfully spatial cues are largely provided by the mains."

The spatial aspects are complicated. In a home listening room, there is in effect a competition between the spatial cues on the recording and the contradictory cues of the listening room. At BEST, we have a poverty of recording venue cues - nothing remotely approaching the veritable plethora of cues at a live performance. The magnificent ear/brain system is able to reconstruct a reasonable approximation of the recording venue (whether real or engineered) if cues consistent with the recording venue effectively dominate over the listening room’s signature. So regarding cues consistent with the recording venue, arguably every little bit helps.

The phase quadrature (90 degrees apart) setting with subs placed wide to the left and right of the listening generally contributes cues which support the perception of being in a large acoustic space, which can help tip our perception towards the venue on the recording, or a reasonable approximation thereof, and away from the distracting awareness that we’re really just sitting in a small room pretending.

Duke
audiokinesis
2,755 posts
 
Kalali asked, "Duke, how do you handle the adjustment of phase at -90 degrees between the two (or four) passive subwoofers while using only one amplifier in the Swarm system? Does this approach require two or more amplifiers each with a separate phase control? " 

In a Swarm system, the 90 degrees apart adjustment calls for a second amplifier.

The amp that I use has a 0-180 degrees continuously-variable phase control. It’s the Dayton Audio SA-1000, available from Parts Express, in case anybody wants to "roll their own" passive multi-sub system.

Duke
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