Thanks for your patience and interest.....
My best to you....
My best to you....
Help me understand "the swarm" in the broader audiophile world
I'm still fairly new out here and am curious about this Swarm thing. I've never owned a subwoofer but I find reading about them--placement, room treatments, nodes, the crawl, etc--fascinating. I'm interested in the concept of the Swarm and the DEBRA systems, and I have a very specific question. The few times I've been in high-end, audiophile stores and asked about the concept of the Swarm, I've tended to get some eye-rolling. They're selling single or paired subwoofers that individually often cost more and sometimes much more than a quartet of inexpensive, modest subs. The same thing can be said for many speaker companies that make both speakers and subs; it's not like I see Vandersteen embracing the use of four Sub 3's.
My question is this: do in fact high-end stores embrace the concept of multiple, inexpensive subs? If not, cynicism aside, why not? Or why doesn't Vandersteen or JL or REL and so on design their own swarm? For those out here who love multiple subs, is it a niche thing? Is it a certain kind of sound that is appealing to certain ears? The true believers proselytize with such zeal that I find it intriguing and even convincing, and yet it's obviously a minority of listeners who do it, even those who have dedicated listening rooms. (I'm talking about the concept of four+ subs, mixed and matched, etc. I know plenty of folks who embrace two subs. And I may be wrong about all my assumptions here--really.)
Now, one favor, respectfully: I understand the concept and don't need to be convinced of why it's great. That's all over literally every post on this forum that mentions the word "sub." I'm really interested in why, as far as I can tell, stores and speaker companies (and maybe most audiophile review sites?) mostly don't go for it--and why, for that matter, many audiophiles don't either (putting aside the obvious reason of room limits). Other than room limitations, why would anyone buy a single JL or REL or Vandy sub when you could spend less and get ... the swarm?
My question is this: do in fact high-end stores embrace the concept of multiple, inexpensive subs? If not, cynicism aside, why not? Or why doesn't Vandersteen or JL or REL and so on design their own swarm? For those out here who love multiple subs, is it a niche thing? Is it a certain kind of sound that is appealing to certain ears? The true believers proselytize with such zeal that I find it intriguing and even convincing, and yet it's obviously a minority of listeners who do it, even those who have dedicated listening rooms. (I'm talking about the concept of four+ subs, mixed and matched, etc. I know plenty of folks who embrace two subs. And I may be wrong about all my assumptions here--really.)
Now, one favor, respectfully: I understand the concept and don't need to be convinced of why it's great. That's all over literally every post on this forum that mentions the word "sub." I'm really interested in why, as far as I can tell, stores and speaker companies (and maybe most audiophile review sites?) mostly don't go for it--and why, for that matter, many audiophiles don't either (putting aside the obvious reason of room limits). Other than room limitations, why would anyone buy a single JL or REL or Vandy sub when you could spend less and get ... the swarm?
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I can tell you this ..... for years I had a surround system with Thiel 3.5s C/FL/FR and 2.2's RL and RR. Five speakers, three flat to near 20hz and two flat to about 35hz. The bass was incredible .... as low as any recording I had (including the St Saen's Organ Symphony) were reproduced with NO room effects whatsoever. I vote for "Swarm". |
@tyray Thanks! Yes, I do have the swarm. I have my mains placed on the long wall with a ceiling facing sub in each front wall corner. These two subs are on the top of metal shelf units. What's nice is being able to place a monoblock lower down on each shelf. The shelves also provide some diffusion in each corner. One floor sub is flush against the right wall facing forward just shy of the first reflection point. (Duke recommends facing them towards the wall with about 3" clearance. I figured facing them forward allows them to be closer to the wall) The other floor sub is flush against the rear wall behind me and to my left. This sub is facing to my left. Since the metal shelf units allow for shelf height adjustments in one inch increments, I have staggered the heights of the two ceiling facing subs. I lowered the left front ceiling facing sub so that it is just a little closer to the ceiling that the floor. FWIW - I find that the ceiling facing subs need a bit more than 3" clearance. I tried facing them away from the ceiling which helped a little. But lowering the right another 6" and the left another 18" really made a noticeable difference. I am now considering raising one of the two floor subs up to just under halfway to the ceiling. Despite the different elevations, Duke's recommendation for reversing polarity on the sub farthest from the mains and removing the port plug on one of the subs in the corner works really well. Though it is difficult to A/B test due to the time it takes to move a sub, adjust the shelf height and muscle the sub back up on the shelf, I can hear a tighter and more even integration with the mains. Can't really describe it other than the music sounding more "correct". Probably because the two ceiling facing subs, due to their lower heights are closer to me and also my ear height while seated in my listening chair. Perhaps, like staggering drivers in some speakers for better time alignment, I am achieving similar results. Now that I have a second Dayton, the next step will be running two subs off each at 90 degrees out of phase. |
Rix, I would forget about open baffle subwoofers. Hold on to your opposed driver balanced force design. Work on creating a very stiff, heavy enclosure design of the right size to support the two drivers. What is the stiffest enclosure shape you could use? If you have more or less advanced woodworking capabilities give me a shout and we can discuss it:) |
@mijostyn - I have full access to a cabinet making shop. I've been splitting planks on a band saw, running them through a thickness planer (before and after), joining the solid cherry wood (often with a biscuit joiner). Attempting to build four units from AcousticFields QRD 17 diffusers plans. I have only just managed to get the materials list for the diffusers, and I am going to have to let my friend program the CNC so I can get table time to cut the panels for assembly. I have some skills, always learning more. I worked for a loudspeaker designer, my system page has photos of my current two pairs of speakers during glue up. I'm probably not going to do steel lined sub woofer enclosures though (so far the most rigid enclosure I have made is high density fiber board, 1.6 times denser than MDF, laminated to steel plate). My larger stand mounts are in the high 90lbs each. Stiffest enclosure shape might actually be a tube with baffles on the ends, not the most practical of shapes though without creating a stand of sorts. I have a Tympnay LAT, it was controlled by a DSP, and I have to say I love the sound and without vibrations. Personal taste obviously, I was hoping a slot loaded W frame would do similar to the LAT. The more I read, the more I want to both elevate and maybe try more subs as well. Sorry I went off SWARM topic, but today whilst trudging through a quagmire I was considering the GIK bass traps and not affecting the SWARM sound. I wondered if it was possible the bass traps simply didn't have the absorption (grunt) power to transform the energy from the subs, though enough to deal with the midbass?? From what I have been reading, and researching, the claims are by many that low frequency waves are very challenging and often traditional fiberglass traps simply don't have the power to deal with them as well as other frequencies. Speculation of course. |
brownsfan: " For those of you using DBA combined with room treatments, did you find that the DBA reduced ringing substantially without room treatments, or should I expect my Swarm to primarily rectify nulls at the MLP and expect that the traps will be required to achieve good decay times?" noble100: My negative experiences with decay times in my room and system actually occurred prior to even using a DBA and concerned the opposite of ringing, which was the truncation of decay times. I've noticed this unnatural and premature cutoff of normal note decay times on both my former pair of Magnepan 2.7QR main speakers, driven by a stereo class D amp, and a pair of 12" subs with built-in class D amps. I'm fairly certain the cause in both cases was the extremely high damping factors characteristic of class D amps in general, which are typically rated in the low thousands as opposed to usually being rated in the low hundreds for class AB amps. The higher the damping factor, the more firmly an amp has control over the starting and stopping of drivers, in my former case the large 623 sq.in. planar-magnetic bass section in each of my former 2.7QR speakers and the 12" dynamic cone woofer drivers in each of my former self-amplified subs. Since replacing my dual self amplified subs 4 yrs ago, with the AK 4-sub Debra DBA powered by a 1K watt class AB amp, I've definitely noticed the bass note decay times are somewhat longer, more accurate and more natural with a total lack of truncation or ringing. I've never experienced boominess or ringing with my DBA, either with zero bass room treatments prior or extensive bass room treatments currently. I seriously doubt you will experience any negative bass performance issues in your room, either. brownsfan: " I guess my plan would be to remove room treatments and optimize the bass response without room treatment, then add back the bass traps judiciously to further improve frequency response and ringing. BTW, mains are down 3 dB at 27 Hz, but I have decent response down to 20Hz or so. Is that a reasonable approach?" noble100: It's an approach, but I really don't believe it's necessary. When I installed extensive room treatments in my room, I just made sure that none of the subs were firing directly into a wall or corner bass trap, ensuring each had at least a small section of bare wall to launch their bass sound waves into and not being in very close proximity to a bass trap. This produced very good results in my room. Your mains already have fairly deep rated bass extension. I think it would be more beneficial for you to pay close attention to the volume and crossover frequency control settings on your subs, as well as the slopes of the subs' crossover filters. Are you planning on using an AK Swarm or Debra complete kit DBA or creating a custom 4-sub DBA using self-amplified subs? I can better tailor my advice knowing the details. brownsfan: " Finally, I've read about the crawl approach to optimal placement on the Audiokinesis site, but I'm thinking of using REW to supplement what I hear. Anyone find REW useful in Swarm sub placement? " noble100: I sequentially and optimally positioned each of my AK Debra subs utilizing the crawl method. I've never used REW or any room correction software/hardware, room analysis or mics but I do recognize their usefulness. My best advice would be to first locate each sub using the crawl method and then utilize REW to further fine tune and verify optimum positioning. Ideally, they'll result in the same position but, if not, it'll be at your discretion. Best wishes, Tim |
@noble100 Always a +1! +1 also to millercarbon for his advocacy in addressing the simple, inexpensive (and at times free) tweaks that most of us tend to ignore. I would just add for those out there attempting the sub elevation route to do the crawl method for any subs on the floor first. In my 9' ceiling 14' x 16' room, I varied elevation of the two ceiling facing subs as a simplified "vertical crawl" method. Latest interesting experiment has been angling the ceiling facing subs to 45 degrees relative to the ceiling. Not sure if this is an accurate description but it seems to have further evened out the tonal balance across the mid to lower frequency range. There is a bit more realism as well in holographics and venue specific acoustics. Also apparent is an increase in sharpness (clarity?) in terms of instrument location and soundstage height. Lower midrange to low presence ringing that I noticed before are now significantly reduced. Working on a ceiling mounted subwoofer isolation system that will allow horizontal and limited vertical placement in any direction. Hanging 2 or more subs from the ceiling would likely exploit the possible sub placements in a truly 3D manner. |
@noble100 , Thanks for your helpful comments Tim. In answer to your question, I have ordered a Swarm system. Interesting comments on your experience with decay times. In my case, REW shows the frequencies at which ringing is observed correspond to peaks in the frequency response curves, so I am pretty sure that these aberrations are due to room modes and not equipment. I've got 3 GIK soffit traps, 3 RealTraps Mondo Traps, and 2 GIK Mega traps in the room, and these did a pretty good job of mitigating modal ringing. What ringing remains is at a very low frequency where trapping struggles. I've also got some speaker cabinet resonance adding to the delayed decay at the lowest frequencies. My thinking on removing the room treatments is that I will likely want to have one sub in a corner, and all of the corners are treated. None of my corner treatments are permanently installed, so removal will be trivial, and doing so will allow me to select the best corner for placement of one sub. My room is dedicated, and I have almost complete freedom to place all 4 subs in all three dimensions. |
@millercarbon -- ... since we all know no one or two subs can ever touch a DBA, then not only do the high-end dealers make money selling you the one sub that can’t work, they get to sell you another. And another. And another. And EQ. And more amps. And room treatments. This is actually an excellent summation, if it weren't for the fact that a pair of subs can work wonders in a more limited number of seating areas. Really, why would you want smooth response most everywhere in the listening room when where you're seated is where you're seated, positioned most likely dead center in front of your main speakers and you're less than a goddamn convention of people? Yes yes, sans DSP and room treatment and what not and just close to an acoustical miracle left for you to savor relatively cheaply, but still; a pair of (not least bigger) subs can do great as well, and not only to the ears of some stubborn dumb asses that don't know any better. I have listened to DBA set-ups, not SWARM's per se but a variety of quad sub systems of greatly different sizes all from 8" DR woofers to 15"-loaded horn subs systems. By far the latter was the best, indeed some of if not the best I've ever heard/felt, but without a shred of a doubt I preferred dual sub set-ups with 2 x 18" ported DR woofers and even more so 15"-loaded tapped horns (from the pro arena), both placed symmetrically to the mains and crossed no lower than 80Hz, compared to asymmetrically placed DBA's with up to 12" DR sealed woofers and crossed somewhat lower. I, indeed we don't know any better? Excuse me, but that would be plain arrogant, or, better yet: ignorant to presume. You're placing yourself on top of a pedestal taking a piss at what you haven't experienced, or if you have it wasn't your cup of tea (to each their own, perhaps?) - fair enough. However, this never gets through, and instead it's the same condescending diatribe again and again against anytime other or LESS (to your mind) than a DBA. You guys love selling the DBA approach, but if bass quality and integration is anything to go by it seems I should be even more prolific with the traits of a pair of big, efficient, symmetrically placed and crossed-no-lower-than-80Hz subs. That's something to savor as well, but the same could, to a perhaps even higher degree than the audiophile resilience to DBA, be leveled: who cares? Let's be clear: what you're getting at is, essentially, spot on. The physics part of subs integration with a DBA gets annoyingly in the way of the audiophile snooty approach that loves what's more expensive is also necessarily better. It's hilarious as it is sad. |
Mine is not likely typical. I tried to integrate subwoofers with Magnepan 0.7's and the subwoofer or pair of them always call attention to themselves without integrating into Magnepans. I wanted a more full bodied bass and I now use a pair of DWM's. My amplifier output transformers have taps at ground (for safety because the tubes run at 1 kV) 4 Ohms to which I connect the 0.7 : negative to ground and positive to the 4 Ohm tap, and the DWM "woofer" elements connected negative of one of them to the 8 Ohm tap, positive of said element to negative element of the second element of the same DWM (two 4 Ohm elements in series) and positive of the second element to the 16 Ohm tap. If you use an SET to work with Magnepans it takes an AM radio station transmitter tube such as an 833A.But I have heard subwoofers demonstrated at a high end store with dynamic element speakers and they improved the sense of image. My guess is a swarm might work with dynamic cone speakers. |
This is actually an excellent summation FIFY. There is no "if" and, or but. Its excellent, period. You're wrong about the 2 seats. The problem with fewer subs, yes you can get good bass at one or two places- but only by having too much elsewhere. The excess energy in these areas as it dissipates muddies the bass everywhere in the room. This is one reason DBA bass is so clean and articulate. You're wrong about the expense. DBA is actually the cheapest most cost effective solution. Yes you can spend a lot but the beauty of it is you can have truly awesome bass easily and for under $3k. There's nothing snooty, hilarious, or sad about it. Your response, I mean. Just another failed put-down. Tiresome, is what I'd call it. |
@millercarbon -- FIFY. You're impervious to views countering yours - not much of a debate in that, only dictation leveled from one to the other. One thing is for sure: you love your own story. You're wrong about the 2 seats. The problem with fewer subs, yes you can get good bass at one or two places- but only by having too much elsewhere. The excess energy in these areas as it dissipates muddies the bass everywhere in the room. This is one reason DBA bass is so clean and articulate. And yet, as stated earlier, we're several to prefer the presentation from 2 big subs vs. 4 smaller DBA's. In some cases this approach calls for mild PEQ and/or room treatment, but in either case it has been the preferred scenario. I'd cherish 2 more big subs like the ones I already have, but - as I've written earlier - space doesn't presently permit. You're wrong about the expense. DBA is actually the cheapest most cost effective solution. Yes you can spend a lot but the beauty of it is you can have truly awesome bass easily and for under $3k. What are you rambling about? On the contrary I'm speaking in defense of DBA - read again: "Let's be clear: what you're getting at is, essentially, spot on. The physics part of subs integration with a DBA gets annoyingly in the way of the audiophile snooty approach that loves what's more expensive is also necessarily better. It's hilarious as it is sad." |
Hello m-db, Duke is just being modest. After Earl Geddes generously bestowed the gift of his amazing DBA concept upon him many years ago, what did Duke do? He took the initiative to develop a 4-sub complete kit finished product that very successfully took advantage of this DBA concept at a very reasonable and affordable price, the Swarm, and has been one of the major advocates for the concept ever since. The Absolute Sound magazine has also awarded the Swarm its prestigious Golden Ear Award multiple times over the years. I believe this definitely qualifies Duke as being a world class Bassist. In fact, I give complete credit to Duke, along with his associate James Romeyn, and Dr. Earl Geddes for my ability to enjoy near sota bass response performance in my room and A/V system on a daily basis. Thank you very much guys, Tim |
Renewed thanks for the lively conversation, which has been more than edifying. I don't have anything to add to the knowledgable posts but I do want to add one more reason for my original question. This thread contains some merited criticism of audiophiles who get stuck in their "snooty" ways, dealers who concentrate on the bottom line, speaker companies that are slow to update their design/marketing plans. There's something else, however, that's difficult for me to wrap my mind around. This forum insists on the importance of every detail, the importance of micromanaging every cable terminal and power source. Which is better for speaker cable elevation, cedar blocks or maple blocks? Where does one get just the right marble or granite for a speaker base? What color interconnects are the most transparent? (Blue ... no ... yellowwwwwwww!) And yet the discussion of multiple-sub array contains almost none of this fastidiousness. It's what academics would call a different discourse. It's by far the most casual approach to sound out here: mix and match inexpensive subs. What brand of subs? It doesn't really matter. What size? Also doesn't really matter. Should they be the same? Maybe, but it doesn't really matter. Where placed? It doesn't matter nearly as much as a single or pair. Connections, watts, power source? Doesn't really matter, relatively speaking. My point is that, as an outsider to these technologies, the tenor of the discussion is completely different. It's not only asking audiophiles to consider a new approach to sound reproduction but asking them to consider a completely different way of thinking about, and talking about, the hobby. |
Rix, the stiffest enclosure would be a sphere. But that is difficult to produce. Next is a cylinder or tube as you suggest. This is a much easier design to deal with and perfect for a balanced force system. Just put a driver in both ends. I'm building 4 of them with 12" Morel drivers. Two in each cabinet. For point source systems crossed over below 80 Hz it really does not matter where you place the subs as long as they are spread out always against a wall or in a corner. For line source systems crossed over above 100 Hz you have to consider the affects on image and the increased power projection a line source has. The best way to do this is by creating subwoofer line source along the front wall. It is still a "swarm" system of sorts just with a more specific radiation pattern. |
I hope this is not too far off topic but a quote here by bdp raised a question regarding dipole bass. Anyone who can offer a knowledgable answer will be appreciated. "The rear wave coming back to the woofer after it bounces off the wall behind it needs to be timed (1 ft. = approximately 1 ms.) so that the front and rear waves are in phase by the time they reach the listening location." I've been aware of this time and distance relationship since reading about the Bell Labs experiments identifying the need to separate direct sound waves from reflected waves by at least 10 ms for clarity. Thus a dipole speaker should be placed at least 5' our from the front wall (5+5=10 ms) for greatest clarity. So how can it be calculated to assure rear waves are in phase for reinforcement? I may be auditioning open baffle speakers, which includes the woofers, so how can I determine potential placement to simplify trial and error? Concerning the swarm, I have heard a demo with that and was impressed. But running wires and placement of four sub boxes will not be an option for me. |
I wondered if it was possible the bass traps simply didn't have the absorption (grunt) power to transform the energy from the subs, though enough to deal with the midbass??The problem is standing waves in the room. Bass traps need to be where the standing waves are when they are reinforcing which sometimes might be near a wall but often is not, and they need to move dynamically from place to place as the frequency of the bass notes change. But they can't do anything about when the standing wave is causing a cancellation. So its an inelegant approach that simply won't solve the problem. |
"The more things change, the more they change." William Shakespeare I have two 15" Rel subs. One is setup at the front of the room on the right hand side and the other is facing towards the front on the left hand side of the room. I'm sure there's something better out there, but I can't imagine spending the money to try and surpass what I have. |
northman: " And yet the discussion of multiple-sub array contains almost none of this fastidiousness. It's what academics would call a different discourse. It's by far the most casual approach to sound out here: mix and match inexpensive subs. What brand of subs? It doesn't really matter. What size? Also doesn't really matter. Should they be the same? Maybe, but it doesn't really matter. Where placed? It doesn't matter nearly as much as a single or pair. Connections, watts, power source? Doesn't really matter, relatively speaking. My point is that, as an outsider to these technologies, the tenor of the discussion is completely different. It's not only asking audiophiles to consider a new approach to sound reproduction but asking them to consider a completely different way of thinking about, and talking about, the hobby." Hello northman, Good points. There actually is a lot of technical, fastidious, scientific and interesting reading material available on-line, supporting the effectiveness of utilizing multiple subs and distributed bass arrays (DBAs) in home audio sized room environments, if you desire to learn more on the subject. I suggest googling the writings of Dr. Earl Geddes, Dr. Floyd Toole, Todd Welti of Harman International and Duke LeJeune of Audio Kinesis for a good sampling. You could also google topics such as "the use of multiple subs for home audio", "distributed bass arrays", " how to obtain better bass performance" along with other topics you may be interested in. The DBA and multiple sub concepts are not really new but the use of subs in home audio has been traditionally shunned by many 'audio purists' in this hobby ever since I started began my journey in it about 45 yrs ago. I've never felt the need to restrict my personal audio knowledge, experiences and adventures to the confines of audio purist approved traditional lore, tropes and dogmas. I've continued to attempt to maintain an open mind, listen well to others' experiences and tried to gain knowledge through personal experience whenever possible. I suggest you attempt to do the same since we all ultimately discover our own personal truths and preferences along the way. I've even found my personal truths and preferences to change and evolve over time utilizing the simple, honest and unfettered approach of judging things on their merits and calling them as you hear or see them There's no denying there'll be a lot to see, learn, experience, reject and object along your personal audio/video journey. Enjoy the journey and I hope you don't mind if I refer to you as 'tiger', 'sparky' or 'young grasshopper' a few times along the way. Later, Tim |
Tim, "young grasshopper" works just fine. At nearly 60, I'm well past my meridian but always young at heart. My wife might use the word "immature," and she wouldn't be alone. The funny thing is that I've haunted stereo stores from New Haven to Maine since I was 16, and I've owned plenty of nice equipment (McIntosh tube amps, Maggies, Bryston, Nakamichi decks, CAL Audio, etc) but I've never taken the deep dive. I can feel myself coming over to the dark side... |
There's something else, however, that's difficult for me to wrap my mind around. This forum insists on the importance of every detail, the importance of micromanaging every cable terminal and power source. Which is better for speaker cable elevation, cedar blocks or maple blocks? Where does one get just the right marble or granite for a speaker base? What color interconnects are the most transparent? (Blue ... no ... yellowwwwwwww!) As me your questions OP, I am not afraid! You gest (I hope) but these are all serious questions. Well maybe not the color. But all the other stuff, yes it matters. Not just saying that. Actually tried and compared different wood, elevators, etc. And yet the discussion of multiple-sub array contains almost none of this fastidiousness. It's what academics would call a different discourse. It's by far the most casual approach to sound out here: mix and match inexpensive subs. What brand of subs? It doesn't really matter. What size? Also doesn't really matter. Should they be the same? Maybe, but it doesn't really matter. Where placed? It doesn't matter nearly as much as a single or pair. Connections, watts, power source? Doesn't really matter, relatively speaking.Good, grasshopper! https://youtu.be/gbNCBVzPYak?t=56 There's two main reasons for this. One being the advantages of DBA are so overwhelming they tend to swamp the usual differences between subs. Things like size and power do matter. Its much better to have four really powerful high quality subs than four puny little cheap ones. Just don't be surprised if those four little ones kick butt on one big one that is much more expensive and powerful, even if it measures better. Its still just one. The other main reason is human beings simply do not hear very low the same as very high. Midrange and treble we localize to within a fraction of an inch. 30 Hz we have no idea whatsoever where its coming from. High frequencies we hear instantly. Low bass, less than a full wave and we don't hear anything at all. Finally there's the equal loudness thing. Really low bass doesn't even register until its much louder than the levels at which we can clearly hear midrange. Add all these up and it pretty well answers all your questions. It also answers the question of why its not more widely adopted. DBA shines a light on the fact our hearing is completely different with low frequencies than high. Therefore our system setup must take these two widely diverging aspects into account. Its a bit of a mental challenge. This may be the time to switch to a more modern movie metaphor and perform a Jedi mind trick. |
Things did not end well for Jaco. I love his playing early on before madness set in. He was homeless - Grace, peace compassion upon them. For students of the art, you might look into dual cone / dual voicecoil push pull drivers with a honeycomb core.... I listen to just such a hyper linear animal. You can almost get there in am opposed driver narrow cabinet... almost |
Good bass is hard, really hard in most rooms. Bass arrays simple make good bass easier. There should be special emphasis on good. They do not magically create great bass, but then it is the rare audiophile with great bass. There are two types of people, those who don't think low frequency bass is directional and accept that bass arrays must work, and those that think bass is directional and who put subs near their speakers invariably creating combing effects when there is bass leakage to higher frequencies either directly or through distortion that invariable is worse than any issues with directionality from a bass array. Bass arrays by reducing peaks can even improve decay time and parasitic environmental vibration. Audiophiles like to talk about fast bass, and then will go into great detail about damping factor, speaker design, woofer diameter and any number of other phantom impacts. Most of the perceived "speed" of bass is room decay. If you want truly fast bass, you have to address your room. A bass array will help you get there, but can't solve all room issues. Most factory car audio systems have faster bass than high end home systems. Those windows may be reflective, but an automotive interior is filled with a lot of absorptive material by volume not to mention material specifically for sound deadening. Listen to how fast the bass is next time you are in the car. |
dannad: " There are two types of people, those who don't think low frequency bass is directional and accept that bass arrays must work, and those that think bass is directional and who put subs near their speakers invariably creating combing effects when there is bass leakage to higher frequencies either directly or through distortion that invariable is worse than any issues with directionality from a bass array." I just wanted to discuss dannard's comment above in a little more detail. I'm definitely in the camp that believes fundamental deep bass tones, under about 80 Hz, are not able to be localized without help from the naturally produced bass harmonics or overtones of these fundamental deep bass tones, that often extend well above 80 Hz and are able to be localized, that are reproduced in stereo through the main speakers. The key ingredient is our brain's amazingly sophisticated sound processing capabilities, developed and refined through the eons of evolution and natural selection to be currently finely honed in the vast majority of extant humans. One of the brain's extraordinary capabilities is the ability to associate the naturally produced bass harmonics or overtones of fundamental deep bass tones, that are above 80 Hz, reproduced in stereo through the main speakers and therefore localizable, with the fundamental deep bass tone itself, that are below 80 Hz, reproduced in mono through the sub(s) and therefore unlocalizable, and creates the perception of localizing the deep fundamental bass tone in space. This whole cerebral associative process, I believe, explains why , as dannard states: " There are two types of people, those who don't think low frequency bass is directional and accept that bass arrays must work, and those that think bass is directional and who put subs near their speakers invariably creating combing effects when there is bass leakage to higher frequencies either directly or through distortion that invariable is worse than any issues with directionality from a bass array." I think there are two types of people as dannard states but I would describe them a bit differently: 1. Those that realize we all perceive deep bass tones below 80 Hz as not directional and therefore utilize bass arrays to obtain excellent bass performance. 2. Those that believe deep bass tones below 80 Hz are directional, place a sub next to each main speaker to reproduce it and believe this configuration is responsible for their perceiving the deep bass below 80 Hz as stereo. However, they're not realizing that their brain's ability to associate the mono fundamental deep bass tones, below 80 Hz that are actually being reproduced by their L+R subs, with the stereo harmonics or overtones, above 80 Hz that are being reproduced by their main speakers, are the real reason they are perceiving the deep bass below 80 Hz as directional and in stereo. In my opinion, an understandable misunderstanding by group#2 above. I don't think it's really a big deal, either, since both groups are ultimately perceiving the mono and nondirectional deep bass below 80 Hz as stereo. Tim |
ONE: Well, if 2 are better than 1, and 4 are better than 2, then are 8 better than 4; are 16 better than 8? 32, 64, 128, 256...? (Is that a straw man argument, or, lacking other evidence, simply taking the argument to its logical conclusion?) TWO: A friend of mine who was the audio guy for the Untied Nations and the DJ for the Nuyorican Poets Cafe gave me a tip, which I have to try over the weekend: Put the sub in the spot where your listening chair is. Then walk around the room. When you find the spot where the bass sounds tightest and deepest, that’s the spot to place the sub. Assuming this theory works, I’m hoping that spot isn’t in front of the door to the room. |
Unreceiveddogma wrote: " Well, if 2 are better than 1, and 4 are better than 2, then are 8 better than 4; are 16 better than 8? 32, 64, 128, 256...? (Is that a straw man argument, or, lacking other evidence, simply taking the argument to its logical conclusion?)" My guess is that (aside from cost) practicality vs perceived utility is what sets the upper limit on the number of subs. For most people, apparently that number is either 0 or 1. For some, it is more. Each additional sub offers LESS incremental improvement than the previous one, simply because there is less net increase in the spatial distribution (assuming the previous subs were intelligently distributed). Where the "point of diminishing returns" lies is arguably a judgment call, again with practicality probably being a major factor. Duke |
I manufacture bass guitar speaker cabinets and sometimes that gives the impression that I'm a bass player. But I'm not. Duke, your Bass cabs look nice, small and solid. Smart. Dust collection is everything, over build it. Don't mess around. I get stoke from most Bass players, past and present. From Guitar / Bass player Kathy Valentine of the Go-Go's to Christian McBride, its all good. In '64 with JBL's DIY plans I cobbled together two 4530 'Scoops' and drove them using a Fender Deluxe with a modified line output to a Marantz 8B for amplification. Lots of plywood on stages in those years. Over the years I acquired a 360/361, Magnavox SVT trunk w/ Tone Tubby drivers, QSC BAG END w/ELF-M sub, Bergantino, Mesa 400+, etc. scattered around the house. Small venue FOH gear came and went, I still have an older Tom Danley horn. Now don't laugh, my current rig is an Acoustic Image Focus driving an old 12" drum shell fitted with a BAG END 10" Coaxial and x/over upshot. Amp and speaker fit in a back pack, holding my Fiddle leaves me a free arm and just one trip to the car. So I began and ended up using DIY cabs. Life, eh? I think you'd enjoy the soup-to-nuts tour of Masa Boogie operation in Petaluma California on your way to Napa valley to pick up a few bottles of Sinskie and Plump Jack. |
unreceivedogma: " A friend of mine who was the audio guy for the Untied Nations and the DJ for the Nuyorican Poets Cafe gave me a tip, which I have to try over the weekend: Put the sub in the spot where your listening chair is. Then walk around the room. When you find the spot where the bass sounds tightest and deepest, that’s the spot to place the sub. Assuming this theory works, I’m hoping that spot isn’t in front of the door to the room." Hello unreceivedogma, Your friend's tip is a good one that I've used and recommended many times with very good success. It's commonly referred to as the 'sub crawl' method and you're highly likely to find it to be very effective in your room as well. If the result is actually in front of a door, placement immediately to the left or right side of the door will probably also result in very good bass perception at your listening seat. This is technically a bit of a bass performance compromise but you can decide for yourself if it's a sufficiently subtle one to be acceptable. Tim |
Right. If we are talking about a 2 channel high fidelity system one sub never works well for a multitude of reasons. When you get to two subs crawling around on all fours is an evolutionary step backwards and totally unnecessary. Sub placement has to consider the placement of the satellites. Whether or not you add more subs in addition and where you place them depends on what type of satellites you have, point source or line source, size of drivers, how high you intend on crossing over and how loud you want to go. Subs should always be against a wall or in corners. There is a large increase in efficiency which lowers distortion and the amount of power needed to drive the sub. It also decreases unfavorable room interactions. By far the most difficult problem is matching the subs to the satellites. If set up correctly you should not be able to tell there is a sub in the system. There are three issues that have to be dealt with to get the job done right. The crossover point and slopes, the phase and time relationship between the subs and the satellites and the relative volume of the subs to the satellites. Subwoofers have a bad reputation in many quarters because getting all this right is not easy and I have not seen a single powered subwoofer that comes with the onboard flexibility to do this well. It becomes a trial and error ordeal. Passive subwoofers with outboard amplifiers and digital crossover systems have the power to do this very effectively in less than a human life span. Now I just pissed off everyone with a powered sub 🥺 Not to worry! You can use the amplifier in the subwoofer you just have to add an outboard crossover with the necessary flexibility. You have to get one anyway as very few subs come with a high pass section for the satellites and you will absolutely never get the best performance without one. |
I must have a magic sub. And here I was thinking I had TWO magic subs.. @noble100 -- Hi, Tim I think there are two types of people as dannard states but I would describe them a bit differently: It’s important to note that for bass to actually appear nondirectional a cross-over somewhat lower than 80Hz must be used. Most may apply no steeper than an 4th order cut-off, and as such (even with steeper cut-offs) residual information will be audible above a, say, 80Hz cross-over and quite easily render sub sources directional. A mono-coupled DBA set-up will thus require a fairly low cross-over, indeed dictate it for best results, and from my chair it’s an undesirable and limiting demand being my preference is for main speaker/subs constellations to be crossed higher, typically between 80-100Hz (which also means high-passing the mains). For this dual sub set-ups work wonderfully, insofar symmetrical placement of the subs close to the mains is upheld for best possible integration and overall balance. It’s not about being uninformed sticking to dual, symmetrically placed subs (close to the mains) - preferably large, at that - but a choice based on preference; indeed, why do I prefer a higher cross-over between the subs and mains in the 80-100Hz region? Because I find it usually sounds better, plain and simple, and here stereo information is suddenly a factor as both it and directionality are factors from sub sources crossed no lower than 80Hz, with residual information from those sub sources audible beyond 100Hz. Moreover: if this (i.e.: DBA) was truly about physics and adhering to that, it’s conspicuous that the sheer size and displacement area of subs isn’t taken more into consideration. This as well is a huge factor, and what may seem overkill to some in this regard is only just an approximation to sufficient headroom to others, with lower distortion and cleaner bass to boot. May I offer yet an alternative summing-up (and this is not as much implied by or addressed at your contributions on the matter, Tim, as that from others):
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¨One need not be a bass player to be inspired by Geddy Lee.¨ @audiokinesis But Geddy Lee does not connect his bass to bass cabinets, he connects them to laundry washing machines, check the videos... just kidding. Thanks so much for the Swarm ideas, I,m about to complete a swarm like system. I already have a two Vandersteeen 2wq subs (active) on my system. I just bought locally a pair of B&W CT SW10 passive subs which are 4 ohms each. A Dayton Sa1000 amp should be arriving in the next few days. I understand that the passive subs should be wired in series in order to not overload the amp. Any other recommendations in to completing this DBA into my system, My main speakers are Gradient Revolutions (dipole bass)which have already a 80hz high pass between pre out to amp because of the way the Vandy subs work. I will be using the other pre output for the Dayton amp. i will appreciate any recommandation you could give me. Thanks a lot |
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@dannad -- In my experience, this arrangement tends to create far more issues than it solves, specifically because of what you mentioned, spectral leakage. For this to work, your speakers need to be phase aligned across the whole shared frequency range of your mains, otherwise you end up with some very strange phase cancellation effects and not just at typical subwoofer frequencies. My speaker set-up is fully active and phase aligned by ear over their entire frequency spectrum. A friend of mine using a dual sub EV TL880D set-up, symmetrically placed, have passive 2-way main speakers (S.P. Tech Revelation) that coheres smoothly with the subs. They’re crossed at ~100Hz and phase aligned here - again, by ear - but with no issues to report in the remaining frequency range - it sounds wonderful. As you write "In my experience" - indeed the imperative words here. Loss of directionality is <120Hz, hence why 80Hz was chosen to allow enough frequency distance for filters to work. You don’t need perfect cutoff at 120Hz, but enough that the mains are at that point significantly dominant in output. Even with a cross-over point to the subs lower than 80Hz, 36dB/octave L-R, we’ve always been been able determine the advantage of symmetrical placement of our individual dual sub systems, so fairly rigid numerical values that would hold otherwise does little do change what’s actually perceived audibly. |
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@dannad -- You lost me at "phase aligned by ear" as I know that is impossible. Not difficult, but impossible as you must have equal slopes on both (after applying high/low pass) including the amps, crossovers if they exist, speakers, etc. It’s hard enough when one has total control over the drivers and cross-over and the proper tools. Even with DSP it can be challenging. Last I looked you didn’t sit in my or our listening room being us, so what exactly is your experience in the context I’m referring to? You may well have a lot of experience in a variety of areas and this matter in particular, good for you, but you’re not familiar with our specific set-ups/rooms nor our preferences, so we’re not getting any further with you dealing out absolutes that we must simply agree with. Crossing over at 100Hz with those big TL880D and with the S.P. Techs there are going to be comb effects. "Sounds wonderful" and not void of issues that could be eliminated are not the same thing. Same as my reply just above. Is it so difficult to fathom that others might think differently on a matter than you? You don’t know enough of the context I’m referring to, i.e.: our specific contexts, and even if you did why would you tell us what we prefer is somehow wrong or a path off-trodden? |
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Moreover: if this (i.e.: DBA) was truly about physics and adhering to that, it’s conspicuous that the sheer size and displacement area of subs isn’t taken more into consideration.Uh... it is. The size of the subs *has* been taken into consideration by Duke of Audiokinesis and that is the beauty of his system. His subs are 1 foot square by 2 feet (using a 10" driver), which is fairly small as subs go, yet they go flat to 20Hz. He gets away with that because they are designed to work in the room boundary effect and so roll off at 3dB/octave starting around 100Hz. This means they have to be placed close to the walls (which usually happen to be more out of the way, resulting in inconspicuous placement in most rooms) in order to work right. It sounds to me from your comment above that you might have missed this bit in the prior conversation. Most subs are not designed to take advantage of the room boundary effect because the right place to put them is likely not against the wall- its where-ever in the room it has to be in order to work. |
@dannad -- Whether I am knowledgeable with your specific setup, I am very knowledgeable about how difficult it is to match the phase response of two completely different speakers, with two different amplification chains, and potentially with some crossover components thrown in. I am also knowledgeable about what happens when you don’t do it highly accurately. I’m not putting into question your being knowledgeable in the areas you point out to me, but what makes your believe what we’ve done with my set-up (or the others I’m referring to) isn’t implemented "highly accurately," if that’s what your saying? I am also knowledgeable about the specific case of main and subs side by side and what the artifacts are when the matching in phase is not really good. I am also knowledgeable that you can’t match that by ear to any good accuracy. If this is the principle basis of your criticism it still goes: you have zero knowledge about the specific implementations in question, so what you have at hand is simply conjecture - end of story. I’ve previously had measurements and digital corrections done of my set-up with different main speakers, passive at that, using DRC Designer (in both time and amplitude domain), and it sounded.. oh well, why bother; what you need is the theory in place according to your head and a set of measurements, right? Currently with my fully active set-up and different speakers I’ve chosen not to implement digital corrections, and yet it’s certainly the sonic scenario of my/our preference. Measurements and digital corrections only get you so far, on their own. They can be helpful, but the final tweaks must be done by ear. That I have not experienced your exact system does not change how the physics of sound and how electronics work. So? Essentially what you contest is based on mains and subs placed side-by-side and our having done phase adjustments per ear, which is hardly the big picture. Sorry, man, this is a dead end. |
@atmasphere Uh... it is. Mr. Karsten, Thank you for pointing this out, not that I wasn’t aware of the boundary effect you mention. My main aim was to go after the scale of the DBA set-ups typically used, not the design principles themselves. I believe size-considerations to make the DBA system commercially viable have been prevalent, which is understandable, but for those wanting to take the bar even higher a bigger scale will be advantageous. |
for those wanting to take the bar even higher a bigger scale will be advantageous.IME what this often means has something to do with sound pressure. Certainly its no worries building subs that go deeper, can do greater sound pressure and the like. But I've seen the Swarm do quite well; in a nutshell, what it allows you to do is in most rooms set up a system where the bass will be superlative. So this in turn allows you to set up a system on a variety of budgets that really can be state of the art in terms of resolution, since the mains really don't have to go below 60Hz. |
IME what this often means has something to do with sound pressure. That's certainly the potential of a scaled-up sub system (i.e.: added SPL capacity through bigger air radiation area/higher sensitivity/ability to take more power and larger overall size), yes, but it's not the goal per se or rather as much as that which relates to added headroom; performance gains at a similar SPL compared to a smaller/less powerful system due to less cone movement and wattage put through the voice coils, and therefore less distortion and cleaner bass. That's the prevailing logic of (more) headroom, and it's far overlooked in audiophilia in general as large size (and very high SPL capabilities) are usually scoffed at, otherwise deemed undesirable (i.e.: WAF, interior decoration) or ridiculed for being overkill. |
