My experience adding subwoofers to 2 channel

bdp24:
"@noble100, I agree, you didn't state that you can't use four Rythmik subs in a swarm type system. Ya know what I didn't say? That you DID say that. Why do you think I think you think you did?"

     Hello bdp24,

     Okay, you may not have said it directly but it's a simple, unambiguous inference to make from your post comment in which you referenced myself, quoted below:

"The plate amps in the Rythmik subs provide all the controls mentioned by @Noble100: volume, phase (180 degrees via a continuously-variable rotary knob), x/o frequency (40-120Hz) and slope (2nd/4th order), plus damping, a rumble filter, one band of PEQ, and both line level (RCA jacks) and speaker level (binding posts) hook-up. There is no reason four of them cannot be implemented as a swarm. You will however need four AC outlets. ;-)"

     In any case, I agree that four Rythmik subs implemented as a DBA have all the required controls and would likely result in a high quality bass system.

Thanks,
  Tim

Tim, I think you need to drop your Adderall dose:) Sub woofers are not more prevalent in high end audio because they add expense, they take up space and women do not like the looks. Not to mention that there are still many audiophiles who think sonically they are a detriment.  All this seems to go the way side when you are talking about theaters. Back in the 70s when I started using subs (RH Labs) I got all kinds of flack from the audiophile community about how they were impossible to integrate and sounded awful and how could I do that to my system la di da. Actually, back then they were right. I started off with one sub and now matter what I did I knew I was listening to a box between my ESLs. So I got another sub and mounted the ESL panels on top of them which made a distinct improvement but I could still hear the cross over. All we had back then was the Dalquist DQ 1. So I spent the next 2 years messing around with the crossover. The system could be impressive but I never though it was accurate. In 1981 I had to move from Miami to Akron so I sold the system to my room mate who had no idea what he was listening too. In Akron I got a set of Acoustat 2+2s and a set of Krell KMA 100s.
In the small apartment I was in I never felt the need for subs with this system which was glorious. In 1987 I sold just the speakers and moved back to New England where I got a pair of Apogee Divas, all the rage at the time. The Divas did not do low bass and I felt that the speakers would sound better if I subtracted the very low end from them. So, I got a pair of the early 12" Velodyn Subs. They were sort of OK but the Divas really perked up. I could never really integrate the subs well enough that they disappeared. Then I got my first TACT preamp with full digital bass management and room control. Instant bliss, huge improvement. But, the two woofers could not match the power of the Divas. Analyzing the situation I realized that the only way I was going to get sub woofers to match the output characteristics of a linear array was to make a linear array with the sub woofers. We are now in the late 90's I think. Looking at the subs available on the market then there was not one that suited my purpose. All I needed was a passive sub. So, I built 4 subs using what is now called the Ultimax 12" sub woofer by Dayton. The enclosures were made of solid surface material laminated to 1" MDF and designed with a Q of 7.4. Each one weights almost 200 lb. I got commercial 1200 watt/ch AB amps with damping factors of 500 into 4 ohms, one for each channel. The subs were arrayed across the front wall at 5 ft intervals but off the wall. This resulted at least 10 db standing waves in the room. I had to get rid of the reflection off the front wall so I spun the middle subs side ways and pushed them right up against the front wall facing each other  The corner subs were already against the side walls. The standing waves all but disappeared. I re calibrated the room control and after five minutes of listening to Return for Forever's Romantic Warrior I knew I finally had it licked. That was with a cross over at 100 Hz I eventually took it up to 125 Hz. Around 2000 I was asked to do a system on the Cape for a friend of my Brothers who I had set up with Acoustat 2+2s years before. He decided to go with Maggies and new electronics (less selfish). When I was finished I was walking out the door and he asked me if I was going to take the speakers. "Do you want me to sell them for you?" "No, you can have them."   So, I inadvertently waltzed  into a pair of mint 2+2s. I sold the Apogees and have never looked back. I guess the moral of the story is that it takes a lot of screwing around to get things right.

What is everyone's take on Hsu subwoofers? They were kind of a hot item a few years ago,but I haven't heard much lately.

mijostyn:
"Tim, I think you need to drop your Adderall dose:) Sub woofers are not more prevalent in high end audio because they add expense, they take up space and women do not like the looks. Not to mention that there are still many audiophiles who think sonically they are a detriment."

Hello mijostyn,
    
     I'm not going to blame my Adderall dosage, it was probably due more to the multiple bottles of whiskey and all those speedballs.
     Concerning your reasons why sub woofers aren't more prevalent in high end audio, you may be correct but I can only respond from my personal perspective.  My subs were an added expense but worth every penny, they don't take up much space at 1x1x2 feet each with 2 not even visible positioned behind my panel speakers, my wife likes the looks of the other 2 that are visible and usually has a vase of fresh cut flowers on one of them. 
      I don't like referring to myself as an audiophile because it reminds me of a crusty old rich pretentious guy blindly following audio doctrines of dubious merit, like the audiophile purist doctrine that subs are sonically a detriment that I envision some audiophiles blindly believing in for decades but never bothering or daring to find out for themselves whether or not the dusty old doctrine even has merit. 
     I consider myself more of a practical, reasonable and independent sort with an open mind, a belief in the scientific method, an appreciation of high quality audio/video equipment but utmost a lover of music and movies who's constantly searching for and learning about improved methods of reproducing both in my home system.  Perhaps I'm such an avid fan of the 4-sub DBA concept because it's so compatible with my concept of myself. 
      You've had a very practical and interesting history with speakers and subs.  I consider Apogees and Acoustats to be very similar to Magnepans, excellent fast type speakers that are a bit lacking in deep bass impact and dynamics that are also all recognized as being difficult to successfully integrate subs with. 
     I'm very curious how well those 4 Dayton subs you built would have integrated with those speakers if you were aware of and utilized the DBA concept  in configuring and positioning them.  Based on my knowledge and experience, I think it's likely they'd have worked very well.


Tim    

Following doctrine gets you absolutely no where. Good for you. I started messing with subs because I knew theoretically they should be a huge benefit particularly with a planar speaker that has limited excursion capability and is a dipole. I would be happy to send you a picture of the whole array. It is set up on a radius from the listing position forming a segment of a circle. The subwoofers are position so that the face of the driver is in the null of the ESLs which is directly to the sides. Dipoles have a figure 8 radiation pattern. Even without room control this works pretty well but without digital bass management, given my experience you are sunk. All the amplifiers are downstairs on a shelf up against the ceiling right under the speakers. The ESLs are 3 feet from the front wall and the subs are positioned so that their drivers are right up against a wall two between the ESLs up against the front wall and two to the outsides up against the side walls. Acoustically these subs are acting as one big driver 16 feet wide forming a linear array of infinite length. Linear arrays like the ESLs do not radiate to the sides, up or down. This is a huge benefit preventing as least 4 of the primary reflections in the room. The result is that no matter where you go in the room except right up against the walls the bass output at any frequency is the same. No standing waves that you can hear. You can not tell there are separate subs in the system. the presentation is one big whole or rather all the speakers disappear. The only disadvantage is that you can tell exactly how bad most recordings are engineered.