My experience adding subwoofers to 2 channel

Oh, and Tim. I am not saying that in certain situations a DBA system may not be the easiest way to reasonable bass performance. It may work reasonable well for many people. What I am saying is that in the end it will not produce the most accurate and realistic results but do to do so usually requires advanced digital speaker control that at this time costs at least $6K. If however you have a tape measure, some savvy and some luck, you might be able to get there without the computer. An important part of this hobby is being able to screw around with your system to see if you can get it to sound better and in doing so you learn. So, start screwing around! 

mijostyn writes:

I’m afraid millercarbon is spouting off with excuses to support his infatuation with SWARM systems, all of which are entirely unsupported assumptions which in reality are entirely wrong.

This is what psychologists call projection. Whatever you are doing you project onto someone else. Instead of actually listening to what they are saying.

Which if you did mijostyn, what you will read if you can be bothered is pretty much everything I have written is based on my actual experience. There is posted among the many threads my actual experience of actually reversing phase, adjusting phase, and trying different locations.

What actually happens- actually not in your imaginary theory world but a real live room- is when you reverse the phase the drum does not disappear. You still hear it. In fact it sounds almost exactly the same. Not quite. You can’t ever change anything and yet have everything be the same. But you said, "Out of phase and you feel nothing." That could hardly be further from the truth.

Now at this point I have to be clear. I’m talking about the lowest bass component only. Of course if you reverse phase on the main speakers the drum is going to go from being focused and located to the opposite, coming from everywhere. At very low frequencies though, and with four subs- which is what we are talking about- its a completely different story. The kick drum does not disappear to "nothing". Talk about unsupported assumptions!

So much for your projecting your own faults onto me. What about your projecting your own misunderstandings onto the Swarm?

You say everything about the SWARM is entirely unsupported assumptions. In fact the distributed bass array concept is based on extensive real world measurement and experimentation. In sharp contrast to your fantasy of it being all "unsupported assumptions" it is in fact only there because of the measurements. In other words it was not a case of a theory in search of evidence. It was the exact opposite of that. It was a case of testing and measurement and then eventually figuring out how to explain why we get those measurements. And only then what to do about it.

Its Audiogon. Someone is always getting something worse than backwards, then posting authoritatively about it. So nothing new here. But just because others do it doesn’t mean you have to follow them over the cliff.

Hello khiak,

  I just sent you a personal message.  You should see a 'dialogue bubble' icon on the upper-right side of your screen, next to the 'shopping cart' icon.  Just click on that and my pm should show. Click on my pm and I think you can hit reply and attach your video clip before sending. 
 I'll re-post on this thread once I receive it.

Tim

Hi Tim, sorry about the delay in answering your question. I hope this helps somewhat.

  Currently subwoofer digital signal processing (DSP) varies a great deal and so too do thier results. My only in home comparrison with a JL Audio F series Automatic Room Optimization ARO v1 was with my old Velodyne DD-18 (v1). 

   Instructions and methods for both differed greatly and can be reviewed and compared on line. For example:
  The JL F v1 uses a limited amount of manual adjustment (at the sub) before and after the internally generated test tone ARO program. Aside from two channel connection instructions there seemed to be little mention of integration with main speakers other than the basic crossover adjustment. 
  The DD (v1) setup procedures include a test tone disc played via CD player were the in room bass roll off of the main speakers and the sub can be viewed from 200Hz on down. Auto-EQ adjusts the level of the eight preset parametric filters from 100Hz on down. Only Manual-EQ allows adjustment of the frequency, bandwidth, and level of these filters and to further tailor the output desired by the user. The sub is not bound by the Auto-EQ or its limits. All DD adjustments can be performed at the listening position using a laptop or by the supplied remote and a TV.   

  The initial equalization results from JLs ARO were different than the DD. After processing the F113 via the DD Auto then Manual-EQ the equalization graph was only slightly different between the two subs. The JL now had better integration and overall presentation. Surprisingly, its 13" driver was every bit as formidable as the DD-18. The JL Audio F series is a great subwoofer.

  Both manufacturers are now using second versions, JLs DARO v2 with an optional CR-1 Crossover and DD Plus. There is a possibility the Funk Farm software could be applied to khiak's 212s which offer a similar amount of cone surface and twice the motor control than the 21.0LXs. 

mijostyn:
" I can not believe people are so far off on the subject of time and phase. Time and phase are intimately related. wire two of your subs backwards and see what you get. That is 180 degrees out of phase."

Hello mijostyn,
     It seems we still have a misunderstanding about time and phase on deep bass sound waves. I believe, at the core of this misunderstanding, is that you're referring to arrival times of deep bass tone frequency soundwaves at the listening position and assuming that the effects of these deep bass soundwave arrival timing are just as critical as they are with midrange and treble tone frequency soundwaves.  
      The owner and speaker designer at Audio Kinesis, Duke Lejeune, has stated that the arrival timing of deep bass tone frequency soundwaves at the listening position are much less critical than the arrival timing at the listening position of midrange and treble frequency soundwaves.  He stated the reason is the extreme differences in the physical length of these sound waves: a 20 Hz bass soundwave is about 56 ft long, a 2,000 Hz midrange sound wave is about 6.75 inches long and a 20,000 Hz soundwave is a fraction of an inch long.  
     I wanted to include a prior post in which I responded to another question from you concerning the time-domain of bass soundwaves that contains similar and some additional relevant info: 

 mijostyn: "You have two subs back there with you and you hear those fractionally before you hear the ones on the front wall. This will smear transients. You want to hear all your subs at exactly the same time."  
    It's my understanding that the time-domain on frequencies under 100 Hz are not as critical as some believe. I also read an article on an experiment proving we don't even detect deep bass sounds until the entire frequency soundwave cycle exists in the room. The experiment consisted of subjects wearing headphones. A series of computer generated partial and full cycle deep bass tone soundwaves were played and the subjects only were able to detect the bass tones in which the full cycle was played and no sound at all when the partial cycles were played. As you know, it takes some time and distance for a full 56 foot long 20 Hz soundwave to develop in a 23 x16 foot room.

     I realize the importance of correct phase in audio reproduction but admit only having a basic understanding.  All 4 of my Audio Kinesis Debra DBA subs are operating in mono and in-phase configurations.  Once all 4 of my subs were optimally positioned, however, I followed the procedures by reversing phase on each sub sequentially, one at a time, to verify whether or not the overall bass response improved with one specific sub's phase reversed. I noticed no improvement with any single sub's phase reversed and, therefore, maintained operating them all configured as in-phase.
     The above is what I learned from scientific research results conducted by acoustical experts Dr. Earl Geddes and Dr. Floyd Toole and Duke Lejeune's posts and writings.  I believe everything I've stated is accurate but you could always refer to their writings if you'd like to verify or learn more.


Tim