Well, my quest to get decent sound in a poor room, on a budget and with strict spousal restrictions, continues... Thanks again to everyone who has helped me so far.
Depending on what more experienced people think, this post could be either my way of paying back a little (as much as I can at my current stage of development) or maybe just another opportunity to discover that I have it wrong. I'm happy both ways.
In a nutshell, here's what I've done: I've created an EQ curve that compensates somewhat for my room acoustics and speakers at my listening position and I intend to place it at the very end of my audio chain and mix through it.
Here's how I did it:
I first did some easy and fairly minimal room treatment that cost very little and didn't upset my wife. I got some shiny new monitors -- Focal Solo6's -- (and I know that I'll have to redo this after they've broken in). I love the new Focals, but I felt (by ear) that things were a bit muddy in the midrange and not quite as punchy in the bass as I expected. My ears have recently been "tuned" a bit by the use of a good pair of headphones -- Sennheiser HD800's -- and a marvellous headphone amp -- the SPL Phonitor. (If I felt that I had enough experience and authority to recommend stuff, I would highly recommend that stuff. Certainly I've never experienced sound that came as close to sitting in front of a real orchestra or jazz ensemble.)
So, I loaded a nice reference song with lots of complexity and frequency range into Logic and used Ozone to take a snapshot of the frequency spectrum averaged over time. Then I put a mic at the position my ears are at when I mix and compared the frequency spectrum that it was hearing to the one that was captured in the box. (BTW, I tried two different mics and the differences were small and understandable, given the nature of the mics. Easy to allow for.) My ears were validated: I could see where the spectrum heard through the mic was deficient in the upper lows and between 1900 and 2300 Hz. That made me feel good. Then I fiddled with the settings on the back of my Solo6's until I made the spectrum as close as I could to reference spectrum. The gaps were smaller, but still there.
Just to see what was going on, I put the mic 18" in front of one speaker and fed it the same audio summed to mono. It was very gratifying to see that the speakers themselves, when almost all room acoustics were taken out of the picture, were able to produce a spectrum that came VERY close to the one taken in the box (with different settings at the back, of course, than those used to try to match at my sitting position). So the deviations at my listening position that I couldn't fix by twiddling the speaker settings were due to the room and not because of limitations of my speakers. (I really like these speakers so far. Of course I really haven't much to compare to -- these are the best speakers I've ever owned and I don't have access to a pro studio.)
Back to the second frequency spectrum... the one at my listening position. I used Ozone's matching function to generate an EQ curve that compensated for the differences between it and the one captured in the box. I then applied it to the 2 bus and listened to the reference song through it. To my ears, the sound was much closer to what I hear listening through my HD800's and the Phonitor. I A/B'd a bunch of times with the EQ on and off, through the speakers and through the 'phones. I did the same for a very different song in a totally different genre (1st was jazz, 2nd was alt rock). Things are still not quite as clear as through the 'phones, of course, the room reverberates and smears the sound a bit, but the frequency spectrum sounds more or less as flat as the 'phones to me; I don't hear any big lumps or holes where I did before. (I should disclose, however, that my ears are still fairly new to mixing and are still improving noticeably year by year -- although they are old to the world. Others would no doubt hear things that I can't yet. This is all pretty rough and ready stuff. Real pros and anal retentives should look away.)
So, to conclude, the EQ thing seems to work, as far as I can hear. I'm not suggesting that this a substitute for a properly treated room, but for those of us that need major renovations to attain acoustic nirvana, I wonder if this can be a viable, zero-cost, low effort mitigating strategy while we plan and save. Or maybe even a way for those who do have fairly nicely treated rooms to take the sound from 80% to 90% -- I imagine that that 10% could be very expensive to get for some rooms, using only acoustic treatment.
What do people think? Is this of value? (I'm worried that maybe not, or others would have thought of it and mentioned it somewhere in this forum.)