After tweaking stuff a little more, cutting the bass a few db, putting spikes on speakers and finalizing their position listening for a while to test tracks I use, I think the room is getting into pretty good shape.
The ETC (impulse) plots are nearly identical from left to right channels. The rt60 is high-ish still, but no noticable room echo or ring (thanks in no small part to the polys
). Well worth the < $60 and time staining and installing.
It is unfair to show a comparison plot between the before and after poly install. Too many variables have changed. What I can say is they seem to offer "air" or smoothing in the high/extended treble ranges. The response plot shows an increase above 4khz right to 8khz of about 5 db. This is great! My speakers are no Axioms...... Their off axis response is kinda ugly. I can only magine what can be accomplished with an Axiom setup.
This is with front corner traps, polys, screen and "good" speaker positioning. I say good because they are toed in to sound like a singer is on a barstool in front of me in the mlp.
Interestingly enough, moving to the next seat over in either direction yields pretty much the same results. Not exact, but the trends are similar over the mid to high frequencies. Bass is almost identical from chair to chair. I attribute this to setting up the row of seating following room mode avoidance rules.
I'm hoping the absorber panels will start to flatten the region below 400Hz or so. This stuff is cool! any predictions? I'm hoping Nick isn't right and I have to redo the front corner traps. Historically..... he's usually right. Lol. I may cover the absorbers right off with 6mil vapour barrier to focus on lower frequencies only. We'll see.
Anyways here we go so far. 1/12th octave scale. Pink noise averaged, yadda yadda yadda.