Which is better for a DBA (Swarm); powered subs or unpowered?

Ha!, Very nice spinaker01. I hope advice from a fellow member of the 4-sub DBA Club (AK Debra system) will suffice for cheeg, instead.
My opinion is that 2 subs will sound and perform about twice as well as 1 sub and 4 subs in a DBA configuration will perform about twice as well as 2.subs. I first heard this opinion from the owner of Audio Kinesis, Duke Lejeune, but I’ve verified it’s accuracy via my own experiences in my own system and 21’x14’ room.
You’ll clearly notice the advantages of using multiple subs beginning with the use of 2 properly positioned subs and these advantages have been proven to be optimized in virtually any room and with any pair of main speakers with the use of 4 properly positioned subs. The advantages you’ll clearly notice are the bass being faster, smoother, more powerful and dynamic, more detailed and better integrated with your main speakers. The main difference between using 4 subs rather than 2 subs is that 4 subs will provide improved bass performance throughout the entire room while 2 subs will restrict this improved bass performance to a single designated listening position or seat. You’ll also notice the bass improves in its speed, smoothness, power and dynamics, detail, sense of effortlessness and integration with your main speakers as you move from using 2 subs to using 4.
No matter how many subs you choose to initially or eventually use, it’s very important you have controls to adjust the following: a regular Volume control for level, a Crossover Frequency for adjusting the frequency below which the subs become active and a Continuously Variable Phase control for fine tuning the sub‘s phase from completely in-phase to inverted phase and all points inbetween. If you use self-amplified subs, all 3 of these controls are required and need to be set on each sub individually. If you use a Dayton SA1000 sub amp/control unit with 2-4 passive (not self-amplified) subs, all 3 controls are set once on the Dayton SA1000 sub amp/control unit for all connected subs as a group.
If budget is a concern, I suggest you start by buying the DaytonSA1000 sub amp/control unit and 2 either used passive subs or 2 new passive subs from Parts Express or Monoprice. If you’re handy, you could save even more $ by building your own subs with kits or individual parts from Parts Express, Monoprice or any other source.
I just recommend you choose subs of reasonable size and weight, with a minimum of 10” drivers, rated bass extension down to at least 20 Hz and 4 ohm impedance if you can. Remember, 2 properly positioned subs will provide very good bass at your designated listening position only, but not throughout your entire room. However, it’s also possible, in some rooms, that 3 properly positioned subs will perform as well as 4 With very good bass throughout your entire room.
There’s also a unique wiring method you need to use for best results called series/parallel which I can detail later if you decide to go with this option.
Another option is to use wireless self-amplified subs such as Syzygy or another brand. I also know the SVS SB-1000 self-amplified subs are very good subs at a great price of $500/each which could work very well for you as either a pair or a swarm.

Tim

Hello cheeg,

     I just read this entire thread and I feel bad for you. The reason is because you’ve been given a lot of bad advice and false information. The majority of this bad advice and false info was delivered by ieales, clearthink and audiorusty. I’m assuming this bad info was due to a lack of knowledge and not intentional but I can’t be certain. You did an admirable job of trying to make sense of it but I think it’s best just to disregard their posts entirely, hit reset and start anew.
It seems like you were already aware of the 4-sub Distributed bass array (DBA) concept. You somehow had learned about how it provides near state of the art bass performance in virtually any room and integrates seamlessly with any pair of main speakers. This is has all been scientifically proven and can be relied upon as valid.      I’ve been thoroughly enjoying an Audio Kinesis Debra 4-sub DBA system in my room for over 5 years now for both music and HT in my 21’x14’ room. The bass is fast, smooth, detailed, as powerful and dynamic as the source material calls for down to 20 Hz and this high quality bass integrates seamlessly with my fast, smooth and detailed main speakers.
    The truth is that a 4-sub DBA system will definitely provide this near state of the art bass reproduction in your room and seamlessly integrate with your main speakers. This will remain true whether you decide to use 4 passive subs powered and controlled by the Dayton SA1000 or 4 self-amplified subs.
      Having the capacity to adjust volume, crossover frequency and phase on each sub individually obviously gives more bass system control. In practice, however, you’ll rarely, if ever, need this level of control and it makes initial setup much more difficult.
     Lastly, I wanted to provide you with some easily verifiable facts that should allow you to more easily recognize the bad information you’ve been given already on this thread as well as any that may be given to you in the future. But I have a meeting I need to attend right now, so I’ll give this info to you later on another post as soon as I can.

Tim

Hello cheeg,

     I’m just going to complete my last post as I previously stated:

Lastly, I wanted to provide you with some easily verifiable facts that should allow you to more easily recognize the bad information you’ve been given already on this thread as well as any that may be given to you in the future. But I have a meeting I need to attend right now, so I’ll give this info to you later on another post as soon as I can. Continuing:

1. Humans cannot localize sounds (determine exactly where they are originating from) with frequencies below about 80 Hz, which includes all the audible deep bass tones down to the audible limit of 20 Hz.  We are increasingly adept at localizing sounds as their frequencies increase from above about 80 Hz to the generally accepted audible upper limit of high pitched sounds of 20,000 Hz.

2.  Recording engineers, of course, have known about this fact since at least about 1950 and is the main reason they’ve been summing all bass tones, with frequencies at or below about 100 Hz, to mono ever since.
     Some individuals will inevitably deny this is true.  I usually just ask them to name a single commercially available recording that contains stereo bass below 100 Hz..  I’ve never been able to name a single example and neither has anyone else.  

3.  It follows logically from the above 2 facts that the reproduction of true stereo deep bass on a home audio system is not possible, as long as commercially available LPs and CDs are the source material played.      Therefore, it makes little sense to position a left and right sub near each of your left and right main speakers.  It’s best just to operate all subs in mono and position them where the bass sounds the best using the crawl method.
 4.  Bass sound waves behave very differently in a given room than midrange and treble sound waves behave.  This is mainly due to the facts that bass sound waves are omnidirectional and very long while midrange and treble sound waves are highly directional and much shorter.  The length of a frsound sound wave is directly and inversely related to its frequency.  The lower the frequency, the longer the corresponding sound wave and the higher the frequency, the shorter the corresponding sound wave.  It’s a continuum with the lowest audible frequency of 20 Hz having a sound wave length of about 56 feet and the highest audible frequency of 20,000 Hz having a sound wave length of a fraction of an inch.
   So, the long omnidirectional bass sound waves are launched into the room from the sub in many directions and, if the frequency is deep and long enough, each sound wave could exceed any single dimension of the room.  Each of these bass sound waves will continue to move out into the room until it meets a room boundary (floor, ceiling or wall), reflect or bounce of  this surface and continue moving in the reflected direction until it meets another room boundary and is reflected once again.  This process continues until the sound wave either collides with another reflected sound wave (causing a standing wave) or it runs out of energy.  

5.  Each time any of these moving and reflecting bass sound waves collide with another sound wave, what’s called as bass standing wave results at the specific room location the collision occurs and we perceive the bass at these exact spots as a bass peak, dip or null.
     If a 4-sub DBA system is utilized, our brains sum and average the bass by frequency and no bass peaks, dips or nulls are perceived in the room.  If only a single sub or pair of subs are utilized, the crawl method can be utilized to ensure the designated listening seat is not located near a bass standing wave.

6.  Interestingly, it’s been proven that a complete,full cycle and full length bass sound wave must exist and be detected by our ears prior to our brains can process it and create the perception of a bass sound at the appropriate depth of pitch in the room 
     If the bass is deep enough that the sound wave exceeds any of the room’s dimensions, this means the sound wave must reflect off at least one room boundary before we perceive a bass sound or tone at all.

7.  Our ears and brains are much less sensitive to the arrival time of bass frequency sound waves than midrange and treble frequency sound waves.  I believe heaudio123 correctly mentioned this earlier on a post.  I’m not absolutely certain, but I believe as long as bas sound waves reach our ears within about one fifth of a second of each other, our brains process these sound waves as related and parts of a single sound or tone.       This means the sound waves from all 4 subs in a swarm definitely do not need to arrive at one’s ears at the same time.  There’s no strict timing requirements or resultant “smearing” involved with multi-sub bass reproduction.

8.  Of course, the much shorter and highly directional midrange and treble sound waves also reflect or bounce off room boundaries (floor,ceiling, walls) until they collide with one another or run out of energy, just as bass sound waves do.        It’s much more important that the main speakers are precisely positioned in the room, and in relation to one’s ears at the designated listening seat, so that the direct midrange and treble sound waves from the speakers arrive at the listener’s ears first, before any reflected sound waves do to ensure optimum performance, imaging and quality.  However, it’s much easier to useroom treatments to absorb or diffuse first reflection points of midrange and treble sound than it is to do the same on first reflection points of bass sound waves.       There’s also no performance, imaging or quality concerns dependent on the direct bass sound waves from any specific, or combination of subs, arriving at the listener’ ears first.  Any midrange and treble sound wave collisions resulting in midrange and treble peaks, dips and nulls at specific locations in the room, are typically not a big issue since we tend to perceive these as an ‘airy’ quality to the overall sound in the room.

Hope these facts helped your understanding,

Tim

While we’re awaiting a presumed response to lewinski01’s questions about 4-sub DBAs from The owner of Audio Kinesis, Duke Lejeune, I just wanted to add a quick comment:

I mostly agree with cleeds comments on his previous post. Based on the comments on this thread thus far from posters questioning the efficacy of 4-sub DBA systems, it is quite obvious that these individuals have never experienced the extremely high quality bass response performance this concept provides in practice in typical home rooms.
There is no smearing, booming or localization. If you can perceive the bass as originating from one of the subs, the system has not been setup properly or the crossover frequency control is set too high-usually above 80 Hz. What you will perceive is powerful bass down to 20 Hz, realistic and natural bass dynamics. The bass will be detailed, accurate in tone and timber and integrate seamlessly with your main speakers regardless of their brand and type.
Even though all 4 subs are run in mono, the bass will still be perceived as stereo. I can explain in detail how this is possible on a future post if anyone would like to know. Individuals have the choice of either buying a complete 4-sub DBA system kit or creating their own custom 4-sub DBA system utilizing their choice of subs. Parametric equalization, room treatments, DSP and auto room correction hardware and software are definitely not required but can be used optionally if preferred.
I’ve been using my AK Debra 4-sub DBA in my system for more than 5 years now for both stereo music and 5.1 surround for HT. I honestly can’t think of how this excellent bass system solution could be improved except with even higher quality, and much more expensive, subs being used.      From my perspective, the only other criticism of a 4-sub DBA I consider valid is that you do need to have, or make, the space for 4 subs in one’s room. I had no trouble accommodating the 4 relatively small, 12”x14.5”x28”and 40#, AK Debra subs in my 21’x14’ room but I realize others may have difficulty.      However,Duke has stated that only 1 of the 4 subs needs to be positioned on the room’s floor, the other 3 subs can be wall mounted on shelves even within a few inches of the ceiling. I know another Audiogon member, named Hans, just successfully and recently installed an AK Swarm DBA in his small office using this method.

Tim