Michael, it was very interesting to read the comparisons which you, Carol and the cats were able to make. On your sub, which I assume is the PB12 which you mentioned before,I would tend to doubt that using a receiver crossover higher than 80hz would be better, at least with the M60s and M22s. The M22s which I have handle that 80-120hz range very well in checking done with a test-tone CD, therefore I think that the 80hz cross is fine(I assume that since the receiver is handling the crossover that you're using the by-pass on the PB12 cross).
You also mentioned sub placement and the general rule is right in the corner. The corner, about equidistant from the floor and both walls, is where the maximum number of room resonances are excited and therefore where the bass is strongest and smoothest. If it's "boomy" there, the idea is to turn down the sub level, not to move the sub.
I think that you'd find that M22s plus sub are extremely close to the M60s; closer than the slightly laid-back M40 mid-range.
