Using Two Subwoofers with Two 2-Channel Amplifiers.

I use 2 REL subs but they're both mono as the aural "ques" for bass position in the soundstage, in either classical or jazz or anything else, is unaffected in my system...the plus is since the subs are doing the same thing they act as moderators for each other by canceling standing waves, which would not happen if only one sub was producing it's stereo signal without the other sub...the subs are set at a low enough frequency (matching where the mains roll off) that stereo imaging is still spot on.

Two channel with subs hard to integrate them together.  But if done correctly can be really amazing.  I strongly recommend:

1) using same amp driving all channels.  The highs, mids and bass.  

2) same interconnects and speaker cables for all unit. 

3) no electronics crossovers Only passive crossovers.

Alot of people think that 60hz and below the bass doesn’t matter when it comes to coherent, huge mistake.  It makes a biggest differences when it comes to two channels critical listening.   

+1 wolf_garcia regarding a monaural or summed below an approximate crossover point depending on the speakers and the room.

With the exception of subwoofers by REL manufactures include the convenience high level connectivity for those who lack source RCA outputs, experimentation should be seriously considered.

Review the subwoofers manufacture instructions when using high/amplifier level connections. Connecting both amplifiers Left channel outputs to one subwoofer seems unusually redundant.

With an honest respect to zipost's experiences. My only sub installation with very small mains that began their in room measured falling off at 97Hz stereo high level connectivity did sound subjectively better to the owner.

With main speakers falling off below 50Hz monaural has always produced a more desirable effect in my experience. It also liberates subwoofers for the always unique crawl test sub locating and an overall improved performance in speed and room node control.   

I am using two stereo JL Audio F-113 subs and I feel that 2 subs fill the room much more than one does. I have mine located close to the mains.

ozzy

Great input everyone, thank you very much.

@wolf_garcia  So if I am understanding you correctly, you have both Left and Right channels wired to both of your Subs?

@m-db  Your "unusually redundant" comment kind of hit home.  It makes sense that If I am dedicating a Sub to L/R channels, it should not matter if a Sub has either one or two Amplifiers connected to it.

Sorry, but just to be clear, when to say "Mono" or "Monaural" you are referring to connecting Left & Right channels to each Sub correct?  My initial thought was that this might confuse the Sub, but it sounds like you guys are saying that this is not necessarily the case (".. canceling standing waves..")

FYI, Mains are two sets of Klipsch Kg-4s.  38 Hz - 20 kHz +/- 3dB at 94 dB SPL.  Room is HUGE (finished basement).