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Other Stuff => Archived Manufacturer Circles => AudioKinesis Loudspeakers => Topic started by: Duke on 11 Feb 2015, 08:20 am
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The AudioKinesis Swarm subwoofer system made the Editor's Choice Awards for 2015, in this February's issue of The Absolute Sound, page 56.
From the entry: "This system is based on the idea that the smoothest, most uniform bass response in a listening room is obtained by using multiple subwoofers in various (usually asymmetric) positions... This idea, says REG, is the answer to bass in rooms... The uniformity of response gives you a compelling impression of being immersed in the bass soundfield of the original venue in a way no single subwoofer can accomplish. REG, review forthcoming."
"Review forthcoming." Yes, there will be a full-length review of the Swarm, written by Robert E. Greene, in an upcoming issue of The Absolute Sound. (Spoiler alert: He likes it.)
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Congratulations. Robert Everist Greene is the most rational, thoughtful and thorough reviewer writing in North America, in my books.
The swarm is a significant concept and deserves attention, since bass reproduction is the biggest problem in most installations, to my ears - almost never right!
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What Russell said!
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Congrats and I'm glad a few people are starting to finally get it :thumb:
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Congrats! Can't wait to get my room sorted and add Swarm. Any plans to add wireless capability?
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Congrats Duke ,
Can you give a brief description on how the Swarm subwoofer system differs from others currently being offered in the market place ..
Regards
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Congrats, Duke. You may not have any real competition. I heard your "Swarm' with a pair of Sound Lab stats and the low end was as transparent as the top end.
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Congratulations Duke, I've been hearing about your swarms for several years now. It's great you are getting some attention for your efforts.
I'm curious, do all of the subs need to be the same, and if so why?
Thanks,
Greg
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That's great, man. Seems like there's not a lot of in-depth info out there about this interesting product.
One question I have... any ideas about using this system with my DSPeaker Anti-Mode Dual Core DAC/pre/proc? Seems like that might be a really powerful arrangement, but I'm unsure how the Dual Core would be connected and 'see' the array.
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Congratulations. Robert Everist Greene is the most rational, thoughtful and thorough reviewer writing in North America, in my books.
The swarm is a significant concept and deserves attention, since bass reproduction is the biggest problem in most installations, to my ears - almost never right!
What Russell said!
Thank you Russell and JLM! Robert Greene is indeed quite thorough. Although TAS doesn't publish measurements, Robert runs them and runs them well. He's an amazing person aside from audio... he turned down a job as head of the mathematics department at Tulane University (arguably an "Ivy League of the South" school) in order to take a position at UCLA, where (as of a few years ago) he was working on developing the multidimensional mathematics and theories for what comes after String Theory. And he participates very actively in a Doberman Pinscher rescue organization... at any given time there are several Dobies living with him and Paige, just getting used to gentle interactions with humans.
Congrats and I'm glad a few people are starting to finally get it :thumb:
As you'll see when the full review comes out, Robert Greene totally gets it. He even identified some advantages of the system that I hadn't really "gotten".
Congrats! Can't wait to get my room sorted and add Swarm. Any plans to add wireless capability?
Alas no, sorry, no plans for a wireless Swarm.
Congrats Duke ,
Can you give a brief description on how the Swarm subwoofer system differs from others currently being offered in the market place ..
The problem the Swarm addresses is, audibly lumpy in-room bass response. This is a fundamental acoustic characteristic of small rooms ("small" meaning "smaller than a recital hall" in this context). This room-induced peak-and-dip pattern will ruin the response of any sub no matter how smooth it starts out, and the Swarm is an acoustic solution to this acoustic problem.
The Swarm consists of four small subs that are intended to be distributed around the room. They are all driven by one central shelf-mounted amplifier. The idea is, each individual sub inevitably generates a room-interaction oeak-and-dip pattern, just like any other sub does. But these peak and dip patterns change dramatically with sub (or listener) location. So with the Swarm, you have four dissimilar peak-and-dip patterns summing at any given listening location.
The net result is far smoother than any one of these patterns could have been without EQ, and this smoothness holds up much better at different listening positions around the room than it would with one or two equalized subs. And "smooth bass" = "fast bass", as it is the peaks in the response that make a subwoofer sound slow (the ear has poor time-domain resolution at low frequencies, so group delay is not nearly as bad as it looks "on paper").
Credit to Earl Geddes for the distributed multisub concept.
The single central amplifier is rated at one kilowatt and has a steep (24 dB per octave) lowpass filter, which is important because we don't want audible lower midrange energy leaking through the subs, especially those that are far away from the main speakers. The amp also has a single band of parametric EQ, useful for addressing any remaining issue. Since the Swarm results in much less spatial variation (that is, variation in frequency response from one location to another within the room), any remaining problem is likely to be global rather than local, and therefore a good candidate for correction via EQ.
One additional characteristic of the Swam modules is what I call "room gain compensation" tuning. This is where the target curve for the subwoofer, before the room's effects, is approximately the inverse of typical room gain due to boundary reinforcement. Room gain due to boundary reinforcement is typically 3 dB per octave, so the Swarm modules approximate a gentle 3 dB per octave rolloff trend from 100 Hz down to 20 Hz. This is more gentle than is practical for an unequalized sealed box, so we use a vented box tuned to give this response. It seems to work quite well. I don't know why more subwoofer manufacturers don't do something like this... if a subwoofer starts out "flat", it will almost always end up with too much energy way down low after the room comes into play, and too much energy way down low = subjectively "slow" bass.
In the event that you get more boundary reinforcement in your room than our room gain compensation tuning was designed for, you can reverse the polarity of one if the subs (which may be beneficial anyway just from the standpoint of response smoothness), and/or you can plug the port on one (or more) of the subs, converting it into a low-Q sealed box. So the system is unusually flexible.
I'm not sure that description qualified as "brief"!
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For a guy who "gets it", he has some rather odd theories about how speakers sound best - when listened to outside. Perhaps he not aware that a listening room is something that should help a speaker sound good rather than act as a determent. Maybe he's not familiar with the concept. Also seems that theory is at odds with your Swarm approach. (Maybe his theory has changed since I stopped reading what he had to say a few years back.)
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Good for you Duke, congrats! Here's hoping the accolades bear you much fruit.
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Question: Who originated the swarm concept, Earl Geddes or Floyd E. Toole (while working for the Canadian Research Council)?
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Somewhere up about Bob Crump is smiling :D
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Congrats, Duke. You may not have any real competition. I heard your "Swarm' with a pair of Sound Lab stats and the low end was as transparent as the top end.
Thank you, Jim!
The original idea for the Swarm was indeed to do a subwoofer system that would "keep up" with planars like Maggies and Quads.
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Over the years I had built a bunch of different types of subwoofers looking for one that would be subjectively fast enough to blend well with dipoles, but with the chest-thumping impact that dipoles lack. I tried sealed boxes, equalized dipoles, EBS vented boxes, aperiodics, transmission lines, isobarics, and maybe others that I can't remember right now. None of them had the"speed" I was looking for.
Then one day, I think it was at CES 2006, I was taking Earl Geddes to the airport. We stopped at the stoplight at Koval and East Harmon. While sitting there, Earl said to me, "Duke, I've figured out how to get good bass in small rooms: Take a bunch of small subs and spread them around the room asymmetrically. The sum of their individual dissimilar peak-and-dip patterns will be smooth." Or words to that effect. I instantly realized that was it, that was the answer to my quest for a dipole-friendly subwoofer technology. So I said, "That's brilliant! Can I license the idea from you?" And he replied, "You can just use it." And then the light changed and we continued on to the airport. Yes, it was that fast, and a part of my world had changed forever.
So interesting Jim that you should mention dipoles, as they figured prominently in the quest that eventually resulted in the Swarm.
Congratulations Duke, I've been hearing about your swarms for several years now. It's great you are getting some attention for your efforts.
I'm curious, do all of the subs need to be the same, and if so why?
In my commercial Swarm system the subs are all the same, but that isn't necessary to get the benefit of a distributed multisub system. In general, the in-room smoothness goes up as the number of independent (not clustered together) bass sources goes up. So two subs are twice as smooth as one, and four subs are twice as smooth as two, and eight subs are a recipe for divorce.
Where I think the Swarm system offers an advantage over just combining a bunch of subs (similar or dissimilar) is:
1) Room-gain-complementary tuning is probably especially beneficial when you have subs transitioning from adding in semi-random-phase in the modal region to in-phase down in the pressure zone;
2) The ability to tailor system to room by reversing polarity on one of the subs and/or plugging ports;
3) The crossover in the amp already has all the features you need; and
4) The Swarm is fairly competitive in quantity of output, not just quality; in a system with dissimilar subs, the smallest one may become the limiting factor well before the others approach their limits.
That's great, man. Seems like there's not a lot of in-depth info out there about this interesting product.
One question I have... any ideas about using this system with my DSPeaker Anti-Mode Dual Core DAC/pre/proc? Seems like that might be a really powerful arrangement, but I'm unsure how the Dual Core would be connected and 'see' the array.
Something like the DSPeaker Anti-Mode unit would work great with the Swarm! You see, the juggling act with EQ'ing a subwoofer is, when you fix a problem in one microphone location, you are usually making it worse somewhere else. The Swarm's reduced spatial variance (see my previous post) means that there is far less frequency response variation from one location to another, so any problems big enough to need fixing are probably global rather than local. So you won't be ruining the response elsewhere in the room as you fix it in one area.
For a guy who "gets it", he has some rather odd theories about how speakers sound best - when listened to outside. Perhaps he not aware that a listening room is something that should help a speaker sound good rather than act as a determent. Maybe he's not familiar with the concept. Also seems that theory is at odds with your Swarm approach. (Maybe his theory has changed since I stopped reading what he had to say a few years back.)
You might want to read Robert's review when it comes out and see if he thinks the Swarm is at odds with his theories of sound reproduction.
Good for you Duke, congrats! Here's hoping the accolades bear you much fruit.
Thank you Ryan! May your line of disgustingly affordable uberspeakers continue to keep your customers and your competitors up late at night, each for their own reasons!
Question: Who originated the swarm concept, Earl Geddes or Floyd E. Toole (while working for the Canadian Research Council)?
That's a very good question, to which I do not know the answer.
It is my understanding that Todd Welti, under the direction of Floyd Toole, undertook his study of symmetrical multisub systems at the same time that Earl Geddes was investigating asymmetrical multisub systems, with each completely unaware of the other's work.
If Toole came up with the distributed multisub concept during his days at NRC in Canada, that may indeed predate Geddes' musings on the subject, but I'm not qualified to say.
Somewhere up about Bob Crump is smiling :D
Did Bob use a multisub system? If so, tell me about it!
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"Did Bob use a multisub system? If so, tell me about it!"
No, he just had a pair of entech woofers, but he spoke highly of you and your wife. Maybe I have the wrong Duke?
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"Did Bob use a multisub system? If so, tell me about it!"
No, he just had a pair of entech woofers, but he spoke highly of you and your wife. Maybe I have the wrong Duke?
I was one of Bob's dealers and a friend and fellow SoundLab fan, and used the JC1's that he helped design. Lori had that "skinny hippie woman" thing going on that Bob had such an appreciation for. She and my sister-in-law would dance on the sidelines in his room at CES. I think I still have one of his little bottles of Snake Oil around here somewhere. Bob Crump is missed by many.
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As a follow-up to an earlier post, Earl Geddes wrote his doctoral thesis on small room acoustics primarily in the modal region back in 1980. I don't know at what point Earl came up with the idea of multiple subs asymmetrically distributed, but he's on record as saying that all of his thinking on low frequency reproduction in small rooms ("small" meaning "any sized room that you'd find in a home") goes back to that study.
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I can't imagine better qualification than this for designing sub woofer systems for home use!!
No wonder it works so well.
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Took a while to get noticed but finally you are getting the accolades you deserve. :thumb:
Seems like I have had the Swarm V2 for years. Great with Soundlabs in an untreated room. :thumb:
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As a follow-up to an earlier post, Earl Geddes wrote his doctoral thesis on small room acoustics primarily in the modal region back in 1980. I don't know at what point Earl came up with the idea of multiple subs asymmetrically distributed, but he's on record as saying that all of his thinking on low frequency reproduction in small rooms ("small" meaning "any sized room that you'd find in a home") goes back to that study.
Yep. There is no doubt this by far the best way to do it.
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Took a while to get noticed but finally you are getting the accolades you deserve. :thumb:
Seems like I have had the Swarm V2 for years. Great with Soundlabs in an untreated room. :thumb:
I had the same thought!
I have been interested in The Swarm for years. My personal audio evolutions moves slowly, like many others must, I presume. But it does seem like this should of gotten some praise from the professional review world years ago.
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It's funny that when I mentioned The Swarm a number of years ago on another audio-centric discussion board, i thought people would be just as interested as I was, but those guys just stamped all over the idea...and a certain audio engineer who frequents this forum, responded with: "I'm sorry but this sounds like an audio salesman or an audio reviewer speaking. I read it as saying if we create enough problems, the ear won't be able to just focus on one or two. (With several randomly placed subs -vs. one deliberately placed badly - I can see why one would think this way.)"
It didn't quite have the snob appeal they were looking for, because then they might have to challenge their own firmly held beliefs if it actually worked. :lol:
I wonder how often Duke had to deal with the obstinate response, "I can localize every one of those subs blindfolded" whenever he tried to demonstrate the theory. If at first the idea is not absurd..... :bomb:
Either way, good to see Duke getting props and hopefully the trend will continue. :thumb:
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Congratulations Duke!
Folks, Duke is one of the best reasons for high end audio.
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Thank you very much, Russell and woodsyi and jtwrace and jriggy! I really appreciate your votes of confidence, coming from your experienced backgrounds.
And thank you too Ralph, top in your field!
It's funny that when I mentioned The Swarm a number of years ago on another audio-centric discussion board, i thought people would be just as interested as I was, but those guys just stamped all over the idea...and a certain audio engineer who frequents this forum, responded with: "I'm sorry but this sounds like an audio salesman or an audio reviewer speaking. I read it as saying if we create enough problems, the ear won't be able to just focus on one or two. (With several randomly placed subs -vs. one deliberately placed badly - I can see why one would think this way.)"
Thank you for your kind words and for sticking up for the Swarm on another forum! Can you tell me where that was? Unfortunately I missed out on the discussion you refer to, but would welcome the chance to reply to analysis and critique from an engineer or anyone else interested enough to discuss the subject.
Actually the observation bolded in your post, presumably made by the engineer. is the beginning of thinking in the right direction. He doesn't come to the right conclusion because he stops too soon, but the acoustic effect of using multiple distributed subwoofers is a much denser peak-and-dip pattern in the modal region. This is analogous to what happens in a large room vs a smaller room... and it sounds better for the same reasons. Those reasons are: 1) The more dense the peak-and-dip patterns the smoother their sum becomes; and 2) the closer together the peaks and dips (another way of saying the same thing), the better the ear/brain system's a 1/3 octave "critical band" averaging mechanism can average out those peaks and dips.
The engineer's intuition leads him to make an understandable mistake: he assumes that a few peaks and dips are less audible than many peaks and dips, when in fact the opposite is true. The reason we don't hear major coloration from room-induced peaks and dips over the upper majority of the spectrum is, those room-induced peaks and dips are bunched up so close together that they effectively form a continuum and the net room contribution is essentially the speaker's power response.
As far as being able to localize every one of those subs blindfolded, that's a setup issue, and isn't a problem if the lowpass filter on the subs is steep enough. It might still be possible to localize them with a carefully chosen test tone, but not with normal program material.
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I found the forum that Larkston Zinaspic mentioned, it's Steve Hoffman's forum. I joined up and attempted to post a response, which will hopefully make it past the moderator(s).
Anyway, here's the guts of what I wrote:
"Unfortunately I was unaware that my Swarm multisub system was being discussed here several years ago, as I would have liked to participate.
"If the topic is still open for discussion, I would like to propose a thought experiment. There will be some simplifying assumptions made, as reality is always more complex than its models, but the idea is to illustrate some of the principles involved.
"Imagine you have a single subwoofer, covering the roughly 1.5 octaves from 60 Hz down to 20 Hz. And let's say that within this passband you have one big (+6 dB) peak and one big (-6 dB) dip at a given listening position.
"Now let's add a second subwoofer to the room, in a significantly different location. Let's assume that it also has one big +6 dB peak and one big -6 dB dip, but because this second sub is in a different location, its peak and dip occur at different frequencies at our listening position.
"The sum of these two dissimilar peak-and-dip patterns will have smaller peaks and dips than either one alone, and more of them (four instead of two). The ONLY WAY that the +/- 6 dB response of the first subwoofer by itself could be preserved would be if the second subwoofer had identical peaks and dips at the exact same frequencies. So with the addition of our second sub in a different location, we now have improved on the +/- 6 dB situation. I think that the most improvement we could ideally hope for in our hypothetical would be to +/- 3 dB, and realistically we'd probably end up somewhere in between.
"Now let's add two more subwoofers. The same smoothing effect would apply, and we'd now have possibly as many as eight smaller-still peaks and dips, though in practice it may not be that many as there would probably be some overlap.
"Anyway the general trend as we add more independent bass sources is a smoothing of the frequency response at any given listening position. In addition, the spatial variation (variation from one location to another within the room) is also reduced.
"I have multiple Swarm customers reporting in-room response of +/- 3 dB across the bass region without EQ, and they are reporting that this improvement holds up over a wide listening area.
"That is the general acoustic theory; there is also a psychoacoustic aspect that we can look at."
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So many are stuck on the Welti / Devantier approach and still having issues. I've been pointing to you, James, Earl and the Swarm for years. I don't think it generated any sales for you guys, but I mostly wanted people to soak up some of that knowledge and apply it to what they already have.
Speaking of which, I am going to be in the market for a sub upgrade later this year, and the Swarm is at the top of my want list. I already have the amp and the system will fit unobtrusively (unlike my 250 lbs. worth of dual 18's :lol:) into my space.
Congrats on the recognition, Duke!
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Congrats Duke! I am glad some are taking notice of good ways to address room acoustics rather than just the sorry old audiophile way of ???
I am planning to do something very similar with my HT room downstairs.
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Duke, congratulations on the much-overdue appreciation for this thinking. I've been extremely happy with the early version Swarm system you sold me to work with my Maggies. It also is a nice complement to the Prisma's! (as if they need all that much help).
It does seem like a crap-shoot when journalists get hold of you. Hopefully this one works in your favor. Here's one of the scattered boxes pretty close to a Maggie in my office.
(http://i817.photobucket.com/albums/zz91/MobysMind/Empire%20Re-Envisioned/2013-02-09202215-Copy_zpscd09fc3c.jpg) (http://s817.photobucket.com/user/MobysMind/media/Empire%20Re-Envisioned/2013-02-09202215-Copy_zpscd09fc3c.jpg.html)
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Thank you, tesseract and Josh and Comet!
That early Swarm did have a nice narrow footprint, and I can see that it comes in handy, Comet. Thanks for posting that image. If the day ever comes that I figure out how to do a "mini-Swarm" and make money on it, I may try to replicate that narrow footprint for its versatility.
Jim Romeyn's "Debra" subwoofer system uses a rectangular footprint, not quite as narrow as the first-generation Swarm, but still more versatile than my square footprint.
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Duke,
Thanks for the explanation. It makes sense to me. My question is, how close can one get using signal processing on a single sub to smooth out the peak and null?
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Duke,
Thanks for the explanation. It makes sense to me. My question is, how close can one get using signal processing on a single sub to smooth out the peak and null?
A single sub can be equalized to be quite smooth at one microphone location, and it can be equalized to offer a compromise improvement over a listening area. The larger the area, the less effective EQ will be a getting a good compromise over that area.
The problem with trying to equalize a single sub is, the peak and dip pattern changes significantly as the listener (or microphone) location changes. And unless you are addressing a problem that is global (throughout the room), it is pretty much inevitable that EQ which significantly improves the response in one location will make it worse somewhere else.
Whether the more limited listening area of an equalized single sub works for you is a matter of personal taste. There are quite a few good room EQ systems out there, and some have algorithms that can give improvements over a listening area, but I do not think they would be as effective with a single sub over a decent-sized listening area as a good multisub system. The multisub configuration is an acoustic solution to what is fundamentally an acoustic problem.
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Congratulations Duke, for this well-earned honor! It must feel great to have now won two awards from respected magazine.
Regarding the issue of proximity effect: even standing directly over a sub in a distributed array, bent down, with my head only a foot or so above the sub, I can not detect whether or not the sub works. I have to reach my hand around and physically contact the woofer.
Normal setup for one sub specifies maximum distance between sub and main speaker at one half wavelength of the crossover frequency. For distributed array I have one sub at the back of a 25.5 foot long room, with seamless blending and no proximity effect even with xo pole set around 70 Hz.
In my last room I spent the equivalent of about $7k on acoustic treatment with mixed results at best. The distributed array works infinitely better.
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Thank you Russell and JLM! Robert Greene is indeed quite thorough. Although TAS doesn't publish measurements, Robert runs them and runs them well. He's an amazing person aside from audio... he turned down a job as head of the mathematics department at Tulane University (arguably an "Ivy League of the South" school) in order to take a position at UCLA, where (as of a few years ago) he was working on developing the multidimensional mathematics and theories for what comes after String Theory. And he participates very actively in a Doberman Pinscher rescue organization... at any given time there are several Dobies living with him and Paige, just getting used to gentle interactions with humans....
It's nice that Robert has so much free time to be a violin virtuoso recording with world class orchestra (he brought his CD into our Newport room). Oh, and still more time to be a linguistic expert such that he tutored Russell Crowe for the movie "A Beautiful Mind." He's also one of the nicest and most caring people you'll ever meet. Duke was not with us at 2014 Newport (thanks to Tony Chipelo for allowing us to share his Electra-Fidelity room). Robert asked how Duke is doing and it was obvious he really cared, it was not just a casual question.
Robert tutored Russell in violin technique for the great movie Master And Commander (realistic early 19th C Navy battleship reenactments). Robert said Russell was one of the hardest working and most dedicated persons he ever met. Russell learned to play violin moderately well (unknown if he had prior music training).
BTW, the sound engineers recorded real live vintage canon for the sound track in the above movie, and when you hear it on SWARM you'll know it's not synthesized. Ironic that even with today's technology no synthesizer could recreate the realism of those canon shots, which are startling.
Canon shots at moderately high level revealed no indication of stress (have the remote handy because canon shots are recorded at proper level relative to dialog and the rest of the sound track).
After my friend retires, he plans to move and build a house with a big sound room. SWARM minimizes anxiety concerning ideal room dimensions related to modal effects. He is a Marine Aviator, and prefers extreme over adequate. I long wondered, and hope to eventually find out, whether eights subs (or even a mere six) might result in +/- 1 dB FR window, minus any EQ of course.
IIRC my room with one sub ideally placed = 13 dB FR window, current distributed array = 6 dB FR window.
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Duke,
Congratulations on the great review of the Swarm System in the April issue of TAS by Robert Greene. He definitely liked it.
Boris
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Thank you very much, James and Boris!
I think I'll start a new thread, as the review goes into a lot more depth than the text that accompanied the Editor's Choice award.