Subwoofers and Phase Question For You Sub Experts

@bdp24 your statement makes sense, I don't completely understand the acoustics behind it, I understand physics and kind of grasp the concept but not entirely. Now the empirical evidence and testing of before and after proves me this solution is perfect, affordable and more importantly something people don't mention scalable, should you move to another bigger house or listening room just add 2 more little subs.

The other things I love about the Vandersteen approach to subs is the way he his amps/x overs mimic the sound of the main amp.  If you spend money on a very expensive amp, his sub amps (AB type) mimic the sound so you don't have that fight either.  It does make a difference to my ears.  

I personally don't like any of the DSP I've heard as it takes away from the sound.  Some are bette than others, but even at the stores that sell DSP, most agree, but it's so easy to set up and most don't listen for the differences as they want it to sound better than analog EQ. ;) 

Auto EQ is soooo variable.  

It is damn convenient and anyone can ise them, but I can understand why many dislike the results.  So, Dirac and JL have good results.

I love my miniDSP but what a PITA to set up right

gosta:"Tried the "swarm" approach and moved four subs into the room but unfortunately found out that they all have about the same tops and dips wherever placed (+/- 20 db from 25 to 100 Hz). So not much of an improvement. Room eq necessary."

Hello gosta,

     As Duke mentioned, something is likely wrong in your positioning of the subs or configuration if you didn’t notice a dramatic bass improvement using a 4-sub DBA in your room. I suggest you may want to answer Duke’s questions to you on his reply if you’d like to figure things out, he knows more about attaining good bass than anybody I’m aware of.
     In the meantime, I thought I’d share how I setup my 4 subs just in case it might work well for you. I have the Audio Kinesis Debra 4-sub DBA system using a single sub amp/control unit. However, I don’t know which 4 subs you’re using, a complete AK Swarm or Debra bass system kit or 4 traditional self-amplified subs. Either should work well, it’s just that you’ll need to adjust the volume, crossover frequency and phase controls on each sub individually if you use traditional self-amplified subs. On the Swarm and Debra, you just need to adjust these controls once on the included amp/control unit for all 4 subs as a group.
     But either way, following my positioning method could be helpful to you:

1. Disconnect your main speakers and move them to another room.
2. Hookup sub#1 and place it at your listening position. If you’re using self-amplified subs, do the same thing but set the volume to 50%, the crossover frequency to 40 and the phase control to "0" (in-phase).
3. Play some music with good and repetitive bass.
4. Starting at the front right corner of your room, slowly begin walking in a counter-clockwise direction around the perimeter of your room listening for the first exact spot that the bass sounds best to you (solid, detailed, dynamic and natural). Take your time, listen carefully and repeat this step until you are certain you’ve found the exact spot.
5. Once you’ve identified the exact spot, move sub#1 from your listening position to this exact spot.
6. Hookup sub#2 and place it at your listening position. If you’re using self-amplified subs, do the same thing but set the volume to 50%, the crossover frequency to 40 and the phase control to "0" (in-phase).
7. Play some music with good and repetitive bass.
8. Starting at sub#1, slowly begin walking in a counter-clockwise direction around the perimeter of your room listening for the next exact spot that the bass sounds best to you (solid, detailed, dynamic and natural). Take your time, listen carefully and repeat this step until you are certain you’ve found the exact spot.

9. Once you’ve identified the exact spot, move sub#2 from your listening position to this exact spot.
10. Repeat this procedure for subs #3 and #4, beginning from sub#2 for placing sub#3 and from sub#3 for placing sub#4.
11. Bring your main speakers back into the room, hook them up and position them optimally in relation to your listening position for midrange/treble and imaging. You now have 2 systems: an independent powerful,fast, smooth,detailed and dynamic bass system as a solid foundation and an independent everything else system consisting of any main speakers you choose to use.

     Once all 4 subs have been positioned, the final step is to optimally set the volume, crossover frequency and phase controls. It’s much easier to do this if you sit at your listening seat and have an assistant adjust the settings at your direction. I achieved the best results by precisely setting the volume and crossover frequency as low as possible with the bass still sounding powerful, fast, smooth, detailed, dynamic and natural. I set the phase at the position at which the bass subjectively sounded the best to me.

     As I mentioned earlier, these 3 settings are set once, for all 4 subs as a group, on the Swarm/Debra amp/control unit but must be individually for each sub if traditional self-amplified subs are utilized.


Hope this helps,
Tim

EQ wont affect phase. Beauty of JL is the continuous phase adjustment.Barry Ober the support guy at JL has some excellent material on their site explaining foolproof phase set up. (reverse polarity on speaker cables, play test tone at crossover frequency, dial phase until you hear the signal null, reconnect cables correct polarity) Check out his stuff.