Been at it again today with REW, but with the Revel M16's in the system as well as my Topping A90 headphone amp in preamp mode since I sold my Schiit Freya+. The little A90 is quite surprising!
Anyway, started with just the Revel's playing by themselves, measuring and adjusting placement of each one separately of course. I'm still getting that 70 Hz peak as I was with the other speakers, but I was able to lessen it some with placement. They ended up about 10" closer to the front wall and about 12" closer together.
After I got the Revel's playing as nicely as possible on their own, I went back to the left channel only and added in the sub, adjusting gain, crossover point, crossover slope, phase and PEQ. Once that one was as good as I could get it, blending with the Revel, I muted that channel and started on the right channel.
Once each channel was to my liking, I then started tweaking them as a stereo pair. More gain adjustments, and more importantly, more phase adjustments on both subs. Not only are the subs blended extremely well with the Revel's, but the subs are "locked in" on each other now, something I wasn't able to do with the other speakers in the system.
I gotta say, this system is sounding splendid right now. With the PEQ and phase on each sub tweaked to the gills, I've been able to smooth out above and a little below that 70 Hz peak, as well as greatly lessen the dips centered around those 45 Hz and 60 Hz nulls.
Stage width and depth have improved drastically, creating a more lifelike, involved and enveloping sound stage. That 70 Hz peak isn't anywhere near as annoying as it was before, and the subs are working together cohesively, not against each other like before. You can easily tell this as the foundation and overall grunt is stronger, tighter and much cleaner now.
Finally, it feels like I'm actually getting somewhere with this system and room. The next big tweaks of course will be room treatments. Most likely, I'll start with some corner traps up front and a couple absorbers on the wall behind me. After that, some diffusers on the front wall. Lastly, most likely a couple more diffusers on the side walls and maybe a couple more smaller absorbers one the side walls right along side my listening seat.
For now, here's a few shots and measurements...
All graphs are with both channels driven.
12 dB Smoothing...
Decay...
Waterfall...
Spectrograph...