Originally Posted by AustinJerry
Couple of comments.
First of all, the bass response in your listening room is comprised of the combined signals from both subs, plus the mains. In order to assess how the bass sounds, which I assume is what you want to do, you should provide the measurement of both subs together, plus the contribution of the mains. I usually measure subs+center because a lot of content for movies comes from the center.
In this measurement, we expect to see a smoothing of those big dips because of the summing of the signals coming from two subs and the center. Look for the smoothness around the crossover frequency. If the response is uneven, adjust the distances of both subs by the same amount, experimenting with different values and observing the effect on the smoothness of the response. This is the "sub distance tweak". If you still see big issues with the flatness of the response, the two options you have are placement of the subs, and adding yet another sub.
The second comment is on the waterfalls. Typically, we show the time slice going to 450ms, where you have it going to only 300ms, which makes the resonance look pretty bad in the examples you posted. You can re-post using 450ms, but if the resonance is still bad, you should consider adding bass traps to improve the bass response. Recsonance makes the bass sound diffuse, less precise, even "tubby". You be the judge--does it sound OK to you?
Doing sweeps as you suggest with all channels running (LCR + SR/SL + 2 subs??), should I do the sweeps with all channels running simultaneously? Or should the sweeps do one channel at a time and then average the responses (if that is even possible)? I've also been running the sub tests up to 200Hz, but I can increase that to 20khz.
I'm using HDMI from a Mac, so I assume I can just create an 8-channel aggregate device to test all channels.
I can also re-run these with all Room Correction and EQ (including Linkwitz Transform and PEQ) turned off, if that's the recommended way to proceed.
I'd say the bass sounds ok at certain frequencies, but there is a subjective lack of mid-bass chest thump. If this is due to the nature of the drivers I'm using, so be it. But I'd like to get whatever I can out of them. Room treatments are not out of the question, but I'd like to do whatever I can with EQ first.
Unfortunately my room is not a regular shape (open floor plan), so modeling room modes doesn't seem to be possible.
Updated waterfall graphs: