Anyone Else Using an Audio Kinesis Swarm or Debra Distributed Bass Array System?


I have Magnepan 2.7QR speakers and posted a similar question about 2 years ago on whether others were using an Audio Kinesis Swarm or Debra or any similar multiple sub distributed bass array system. I thought it might be useful for members to learn about this type of solution for attaining excellent bass performance in virtually any room and with any main speakers for both 2-ch stereo music and ht. I thought a new thread detailing this effective solution may be helpful and attract responses from other users of a distributed array sub system. I’m also wondering if there are any more members using one of these bass systems since I posted my original thread 2 yrs ago.


About 3 years ago I purchased the Audio Kinesis DEBRA (Distributed-Eq BassReflex Array) sub system from James Romeyn Music and Audio in Utah. Here’s a link describing the system:

http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd...

This system is a bargain at $2,500 and well worth the investment. I rationalized the price by noting it’s about the same as a pair of very good regular subs.


The performance of this system in my 23’ x 14’ living room is excellent. The bass can be fast, tight and tuneful for music or loud and impactful for music and home theater. The subs seem to disappear since there are no audible clues to their locations; the bass is very well integrated into the music and movies.

From my personal experience, I was not convinced at the time of the reality of perceiving stereo bass but was willing to give it a try. I was originally thinking of buying 2 high quality subs such as Rhythmik, SVS, JL, Martin/Logan, Vandersteen or REL. I was skeptical of the DEBRA system at first but, after reading a lot of research about multiple sub systems on the internet, I decided to give it a try and I’m now very thankful that I did.

Because it is such an ideal system for me, and because I think it would work well in almost any room or system, I want to go into more detail about the system, its setup and the theory behind it. I have no affiliation with the company but will admit, after considerable phone and email time with the dealer, that I now consider James Romeyn a friend of mine but don’t know if he feels likewise.

The system consists of the following:

A dedicated Dayton Audio mono class A/B amp rated at 950 watts @ 4 ohms with dual A&B spkr output terminals.

Four 44lb. bass-reflex subs that measure a relatively small 23.75" H x 14.5" W x 10.375" D.

Each sub is ported on the bottom, supported by 3 spiked cones and contains a single 10" 4 ohm driver. The subs are designed to be facing, and within 2" of, the room walls.

The setup procedure is:

Sub#1 is hooked up and placed on its back (driver facing the ceiling) at the normal listening position. Music is played that has good and repetitive bass.

Walk around the edges of the room and determine exactly where the bass sounds best to you.

Attach the 3 spiked footers (flat adapters are also supplied for use on non-carpeted floors) to Sub#1 and position it upright facing the nearest wall to the spot you determined the bass sounded best.

Sub#2 is hooked up and placed on its back at the primary listening position. With sub 1 & 2 playing, continue walking around the edges of your room and determine again where the bass sounds best to you.

Attach the 3 spiked footers to Sub#2 and position it upright facing the nearest wall to the spot you determined the bass sounded best.

Repeat this procedure for sub 3 & 4.

Small positioning adjustments may need to be made for each sub due to avoiding furniture and the WAF.

Once completed, final sub hook up is done in series/parallel:

Attach a single wire from the amp’s speaker A’s pos. output terminal and to Sub#1’s pos. input terminal.

Attach a single wire from the amp’s speaker A’s neg. output terminal and to Sub#2’s neg. input terminal.

Attach a single wire from Sub#1’s neg. input terminal to Sub#2’s pos. input terminal.

Attach Sub 3 & 4 using this parallel method on the amp’s speaker B’s output terminals.

I ordered single, high quality and low gauge speaker wire along with the sub system for a very reasonable price. Once the ideal locations for the subs was determined, I drilled holes in my room’s floor to the crawl space below, and was able to hide the connecting wires.

I’m definitely not an expert on subs or room acoustics but, from my reading, here is how I understand the theory behind the distributed array sub systems:

The lower the frequency the longer the sound wave produced, or launched, into a room.

Since these waves can be even longer than the actual dimensions in many rooms, these low frequency waves bounce off room surfaces and the music may dictate subsequent bass waves being launched into this acoustic environment. These initial waves, their reflections and subsequent bass waves inevitably collide and cause ’standing waves’.

Areas in the room where sound waves meet can make the bass sound under emphasized, over emphasized or even totally missing (nulls caused by wave cancelation).

When one sub is launching low frequency waves from 1 specific location, areas in a specific room where bass response is not accurate will be numerous and predictable based on sub location and room dimensions.

Adding a 2nd sub to the room will decrease standing waves and increase bass accuracy and bass dispersion.

According to scientific studies I read (mainly Dr.Earl Geddes and Dr.Floyd O’Toole White Papers), standing waves are reduced, and bass accuracy and dispersion increased, as more subs are used in a given room. Their experiments utilized more subs than anyone would even consider for home use. They basically concluded that the more subs in a room, the fewer standing waves are produced/perceived and the better the bass quality and bass dispersion results.

However, they determined that most of the benefits are gained with the use of 4 subs, with only minimal and incremental gains in performance attained through additional subs. Due to practical room considerations, the researchers recommended 4 subs for an effective distributed bass array system. Here’s a link to an Absolute Sound review of the Audio Kinesis Swarm system which is almost identical to the Debra system I own:

http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

So that’s the equipment, set-up and the theory behind the DEBRA system and I can personally attest to its effectiveness in my room. I have 6 listening/viewing positions in my combination music and ht system in my living room. Bass response is equally good at all 6 positions without the use of acoustic devices (no absorbing or diffusing panels or bass traps) and without any electronic equalization (room analysis/correction equipment, software or eq). I should mention I’ve never had my system/room analyzed using a mike and software. From my purely subjective perspective, however, I’m confident the results would be good since I spent hours on the setup and critical listening from all six listening positions in my room. I would suggest this type of sub system as a viable alternative for anyone considering investing in one or more quality subs. The system is rated clean at 113 decibels at 20 hz. I’ve often heard and felt it go much lower. It feels and sounds clean and right but I can’t verify the decibels or lack of distortion.

Sorry this turned out so long and windy,

Tim

Also, my system photos are updated showing my current system with the subs and new electronics.



128x128noble100
I've shown at shows with the Swarm (and Duke's speakers, which are always well thought out...). IMO/IME the Swarm is one of the best subwoofer systems available.
" IMO/IME the Swarm is one of the best subwoofer systems available."

Hi Ralph/atmasphere,

     I've been singing the praises of the Audio Kinesis Swarm/Debra distributed bass array systems ad nauseam ever since I began using one in my system about 3 yrs ago. 
     I had no idea that you're so familiar with the virtues of the Swarm subwoofer system and that you've used it at some shows.  Of course, I recognize that my often stated opinion of how well the distributed bass array concept actually works in virtually any room can be, and likely is, often easily dismissed as just the endorsement of a 'fan boy' attempting to rationalize a significant system purchase.  
     I believe your opinion and comment that "the Swarm is one of the best subwoofer systems available", however, understandably carries more weight and may result in more individuals taking the distributed bass array concept more seriously and consider its use in their own systems.
     It's continued to be perplexing to me why the DBA concept is not more widely known and utilized, especially by members of an audiophile forum and the fact that the concept has been scientifically proven while also being validated repeatedly since both scientifically by many and anecdotally in their own systems by apparently just a handful.
     Most are aware that good bass response is typically harder to attain in most systems and rooms than good mid-range and treble response.  Using and knowing that a DBA is such a good universal solution that seems to improve bass response almost magically, I was motivated to try to spread the word.  But I remain a bit confused and frustrated that more individuals are seemingly not embracing the DBA system solution.  

Thanks,
 Tim
I had used Duke’s AudioKinesis Jazz modules for many years and was always intrigued by the Swarm. I actually took a slightly different route. I use a 4 woofer array the concept of which came from Roger Modjeski at Music Reference. The boxes have a smaller footprint (1.4 cu. ft. internal dimensions), use 8" drivers, and are sealed. Their resonance is 100 Hz. I use the Beveridge RM-3 active crossover with 4th Order Linkwitz-Riley 100 Hz high and low pass filters. The amp is a Luxman M-02 which I like because it has two sets of speaker outputs so I can attach one pair of woofers to the speaker A binding posts and one pair to the speaker B binding posts. I just placed the woofers asymmetrically around the room and was done with it. Occasionally I like to invert the leads on one or more of the woofers to hear the different effects, but I just end up switching them back.

I am curious about your series/parallel set up and the reasoning behind it. It may be something I might like to try.
Hi clio09,

The series/parallel hookup for the Swarm/Debra systems is what Audio Kinesis instructs in the manual. I had never heard of series/parallel connections and always thought wiring connections could be done either in series or parallel but not a combo of the two.
As I understand it, the series/parallel connection method is used because the amp operates under a recognized single 4 ohm load even though the amp is actually powering four 4 ohm subs, 2 each on both the A and B speaker outputs on the class AB 1K watt amp.
It’s interesting that you occasionally invert the polarity on 1 or more of your subs. The Swarm/Debra manual also instructs to try this on each sub sequentially to determine if the bass sounds better with the polarity inverted one particular sub of the 4. I haven’t bothered trying this yet since the whole system is performing so well as is. Have you noticed beneficial results from doing this?

Your system also demonstrates an important factor when configuring an effective distributed bass array system: the critical requirement is using 4 subs so that the vast majority of bass standing waves are eliminated and, therefore, bass response performance is maximized.

The main points being that the subs don’t need to be a complete set of 4 Swarm/Debra subs, of the same brand or even of the same size. The critical points being that 2 subs will perform better than 1, 3 will perform better than 2, 4 will perform best and any subs added beyond 4 will result in only smaller marginal improvements in in-room bass response

Tim
Tim,

My understanding is that inverting one of the woofers would further reduce bass energy. I did try it but did not notice a difference. Probably because I lucked out and placed the woofers in proper positions from the get go. Inverting two woofers was noticeably worse. I doubt I will try the series/parallel connection. My woofers are 8 ohms and the amps speakers connections when using the A & B speaker connections recommend an 8 - 16 ohm load.