What is current thinking about tilting speakers back rather than raising them off the ground ? I just did that with my M60s -- in my case I was looking for ways to reduce toe-in without losing the stereo image -- and so far I'm very happy with the results.
The speakers were in a slightly unusual setup, in the sense that they were (a) pretty close to the listening position, (b) as far apart as you would want to go (equilateral-triangle-ish), and (c) I'm 6'5 and sit with my ears even higher because the couch is lifted 4" to make it "normal height" for me.
Until now I had had to choose between moderate toe-in (where the frequency response seemed right but imaging was iffy and there was pronounced phasing/comb-filtering when I moved my head from side to side) and significant toe-in (much better imaging but frequency response seem harsh, almost the dreaded "bright").
After tilting the speakers up with pieces of 1x2 laying flat on the ground (so the midrange axis went through ear level rather than navel level) I was able to go back to a very minor toe-in while still maintaining good imaging. The bonus was that the frequency response went back to sounding very neutral, so win-win.
Not quite sure why there is such a difference though. AFAICS my ears are off-axis about as much now as they were before, only now the direction is "mostly off to the side" rather than "mostly up and a bit to the side".
Haven't tried raising the M60s on platforms in their current location and probably won't bother. I did raise them when they were up in the HT, but with an 80 Hz cutoff to the subs I wouldn't expect that to cause many problems.
I don't seem to see any discussion about tilting speakers up these days -- maybe everyone is just buying taller speakers instead
EDIT -- seems like the smoother sound let me turn the volume up a bit higher, and that has the predictable "everything sounds better" result. Wonder if that might be a factor in eggman's experience re: making bass sound better & amp seem more powerful ?