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Congrats diving into the deep end!! There is a lot to gain.
You should evaluate the chart without any smoothing at all. Modes can hide within a couple Hertz.
Yes it is a lot of decay in the bass. Do you have concrete walls?
Use modecalc to see what freq your potential room modes are, and what dimension is causing the problem modes you see on the scan.
Cool I find decay plots easier to use than waterfalls - http://www.hifizine.com/2011/06/bass-integration-guide-part-1/Do you have sub/s? Some experiments in different positions would be illuminating.
I love the learning too!! That's the best part!Nice job on the bass adjustments. That scan looks excellent! You are lucky to have a nice sounding room. From 80Hz on up is about as good as you can expect from residential room. The double sheetrocks helped a lot. Sheetrock absorbs some bass energy, plus there's probably thick insulation between the units. You can add more treatments to make it even better. Ignore the comb filtering spikes in higher freqs. You can hear them but your brain is already adjusted to the sound of the room so it is not a distraction. To kill them means wall to wall coverage, "like a recording studio," as my wife says in disgust.
If you have infinite phase adjustment, adjust it on each sub separately, using a test tone at your crossover freq and a SPL meter. Robert Harley once posted a good idea how to adjust it. http://www.avguide.com/forums/subwoofer-phase Of course you can't control the phase of bass freq echos which effect phase, but the direct sound is worth dialing in. Then adjust the sub levels again. If it's not adjustable, move the subs into phase by their position. But this limits the ability to improve the modes by moving the subs.Subs are rarely as fast as your main speakers' woofer, so the higher the sub plays you will hear more "thickness" in male voices and tenor sax, cello, etc. You might like some fattening, but too much will lose resolution. It would be better to boost the midwoofer with EQ if you want it louder than to ask the sub do a job it is not designed to handle. This is the area in which sub phase error is heard, in the crossover band. If the phase is not adjusted, a 12dB slope at 100Hz will smear well into mids (800Hz) before it is -40dB and inaudible.
It's hard to adjust all this stuff to perfection. There's no perfection, only improvements and saving for better gear and better rooms in the future. Also remember that better on paper is not necessarily better for you. If you like symphonies or dance music, you might prefer +6-10dB in the bass, just like you had it set before! It's all about the music. Measurements / technology are a totally different hobby than music listening. But many people like both hobbies which complement each other...
(excuse the PM, I couldn't get the whole message to post because I didn't have the URL tags around the link.)
I have four dipole (open baffle) 15" woofers
Excessive decay times and ringing can certainly mask bass detail. Another thing is that when the bass rings for long periods, it tends to cancel itself out - not to mention masking imaging cues, harmonic details etc.Tri Traps can certainly help with decay times. For the modal problems, we would need to identify where they're coming from in order to understand how best and where to address them. If the room has an 8' ceiling, that's a common culprit for the 70Hz peak. May not be all of it but certainly a factor.Bryan
If you can, try moving them closer to you and further from the wall. I found having them on either side of me to be particularly (and measurably) effective.
