Ok, so relative to my post above, I decided to run a y-adapter from one of the subwoofer channels and connected both subs to it to accomplish getting a test tone directly from the AVR to both subs simultaneously. What I found is a bit puzzling. I set the 3020 subwoofer trim to 0 db and sub PEQ to flat (for now), and then level-matched each subwoofer to 75 db using the volume knobs on each sub. After running some tests, I'm getting about a +6 db gain running both subs vs running just one. War Of The Worlds never sounded better in my room. Cool.
Now, the strange thing is, while making no other changes except for level matching and removing the y-adapter and running the subs directly from the subwoofer channels, I see no such improvement. The most I can get is about a 2.5 db increase in SPL between running one sub vs running both. I've tweaked the phase settings and used the variable phase adjustment as well on the subs, and also tried adjusting the distance (delay) +/- .2 steps at at time while having the phase on 0 deg or "normal" in the AVR as well as both subs, and I still can't get more than 2.5 db using both subwooofer channels on the 3020.
I have checked and rechecked that the 3020 is set to Mono and not Stereo in the Configuration menu. I also decided to try the y-adapter on Sub Channel 2 (originally on Sub Channel 1), and I get the same kick-butt +6 db response as with Sub Channel 1.
For the record, I am running different subs, a PSA XV15 and an MFW-15, but I don't see where that would have any effect on the response using both subwoofer outputs vs the y-adapter.
Anyone have a clue on this? Am I'm doing something wrong here?
Defeat of Deduct must go over Defense before Detail does.