Hello stickman451,
If you read the article on multiple subs I linked to in my last post, you'll have noticed they recommend the use of mics, a computer, room frequency response analysis software and other technical equipment and procedures for the purpose of optimally positioning each of the multiple subs in the room.
I just wanted to mention that, while this technical positioning method is very accurate and effective, there is a much less technical and expensive method that I've found to be just as accurate and effective called the 'crawl method'. You can google the name for procedure details or I could describe them to you if you're interested, but it's basically a method whereby you use your ears and brain, to sequentially and optimally position each of the number of multiple subs you decide to use in your system and room.
I've used both sub positioning methods in my medium sized room to optimally position my four subs and the final sub position results were remarkably similar with each, two subs away from the corners and at opposite sides along my front short wall and one sub toward the rear of my room along each longer side wall, also a few feet away from the room corners.
In your case attempting to optimally position three subs, I suggest the following:
1. Make sure each sub used has separate controls for volume, crossover cutoff frequency and a continuously variable control for phase.
2. Do not just place your three subs where it's most convenient, you feel they look best or you think they will perform best.
3. For positioning, set the sub's volume control at halfway (50%), the crossover cutoff frequency at 40 Hz and the phase control to in-phase (0). These are just initial settings for setup and can be fine tuned for optimum performance afterward.
I recommend that you carefully and systematically position each sub optimally in your room one after the other by closely following either the measurement or crawl method procedure, placing each exactly where you determine each sounds or measures best and then only judging the results after all three have been optimally positioned in your room.
I recommend you operate all your subs in mono mode, since we're unable to localize bass below about 80 Hz, virtually all music recordings sum the bass content to mono at or below about 100 Hz and, therefore, attaining stereo deep bass reproduction is not possible.
I also recommend you run your 20.7s full-range since they have fairly good bass rated bass extension of down to 25 Hz, which is almost down to the audible bass limit of 20 Hz, and they'll act as two legitimate deep bass transducers in your room in addition to your three subs. This will result in even smoother, faster and more detailed overall bass response throughout your entire room that will be even more powerful, dynamic and with a greater sense of ease than if you restrict their deep bass output.
You should be aware, however, that some believe that using subs for bass reproduction, and relieving the main amp and speakers from the responsibility for this bass reproduction either through high-pass filters in the sub or separate filtering, results in significant overall system improvements in midrange, treble and imaging performance. I didn't notice significant improvements on my system, with D-Sonic M3-600-M high powered class D monoblock amps and 3.7i main speakers, but this doesn't mean you won't be able to with your system. You may want to experiment, audition and compare before deciding on a preferred system configuration.
Best wishes,
Tim
If you read the article on multiple subs I linked to in my last post, you'll have noticed they recommend the use of mics, a computer, room frequency response analysis software and other technical equipment and procedures for the purpose of optimally positioning each of the multiple subs in the room.
I just wanted to mention that, while this technical positioning method is very accurate and effective, there is a much less technical and expensive method that I've found to be just as accurate and effective called the 'crawl method'. You can google the name for procedure details or I could describe them to you if you're interested, but it's basically a method whereby you use your ears and brain, to sequentially and optimally position each of the number of multiple subs you decide to use in your system and room.
I've used both sub positioning methods in my medium sized room to optimally position my four subs and the final sub position results were remarkably similar with each, two subs away from the corners and at opposite sides along my front short wall and one sub toward the rear of my room along each longer side wall, also a few feet away from the room corners.
In your case attempting to optimally position three subs, I suggest the following:
1. Make sure each sub used has separate controls for volume, crossover cutoff frequency and a continuously variable control for phase.
2. Do not just place your three subs where it's most convenient, you feel they look best or you think they will perform best.
3. For positioning, set the sub's volume control at halfway (50%), the crossover cutoff frequency at 40 Hz and the phase control to in-phase (0). These are just initial settings for setup and can be fine tuned for optimum performance afterward.
I recommend that you carefully and systematically position each sub optimally in your room one after the other by closely following either the measurement or crawl method procedure, placing each exactly where you determine each sounds or measures best and then only judging the results after all three have been optimally positioned in your room.
I recommend you operate all your subs in mono mode, since we're unable to localize bass below about 80 Hz, virtually all music recordings sum the bass content to mono at or below about 100 Hz and, therefore, attaining stereo deep bass reproduction is not possible.
I also recommend you run your 20.7s full-range since they have fairly good bass rated bass extension of down to 25 Hz, which is almost down to the audible bass limit of 20 Hz, and they'll act as two legitimate deep bass transducers in your room in addition to your three subs. This will result in even smoother, faster and more detailed overall bass response throughout your entire room that will be even more powerful, dynamic and with a greater sense of ease than if you restrict their deep bass output.
You should be aware, however, that some believe that using subs for bass reproduction, and relieving the main amp and speakers from the responsibility for this bass reproduction either through high-pass filters in the sub or separate filtering, results in significant overall system improvements in midrange, treble and imaging performance. I didn't notice significant improvements on my system, with D-Sonic M3-600-M high powered class D monoblock amps and 3.7i main speakers, but this doesn't mean you won't be able to with your system. You may want to experiment, audition and compare before deciding on a preferred system configuration.
Best wishes,
Tim