^ Thanks. I don't mean to imply any of the dryness and brittleness (for lack of knowing any better way to describe it) is the result of either the S150s or the S300s. There have been various differences in my auditions of speakers including different sources, amps, receivers, and listening rooms. The S300s were never a realistic proposition for me due to size and budget. However I traveled about 1500 miles from home to audition the S150s, and the dealer also had the S300s set up in his living room, so I thought I should take advantage of the rare opportunity to check them out. Most of the dealers in the United States are custom installers, and I found it very rare that anyone was set up to demo any of the speakers at all. There also happened to be a Best Buy/Magnolia store near the dealer I visited that had an older S150 setup in a theater room that I was able to demo. Neither of them had any of the tri-pole surround speakers set up.
At the Magnolia store I just listened to the movie they had playing, but I was using a CD I'm familiar with to demo at the dealer. It contains orchestral music that I've found to be very revealing when played 2 channel. The thin, brittle, dry sound becomes very evident on this and one other CD that I have. The 100+ piece orchestra with some unique instruments just sounds weak and dry. Low notes on the grand piano, bass trombone, tuba, bass cello, etc. seem weak and dry when they should be bold and rich. This is much less noticeable on other music and multi-channel movies. I've heard some of the music from the CD played through a theater speaker system and it doesn't sound this way. It also sounds rich with some headphones. Anyway, I was surprised to find that simply reducing a boost that my Pioneer's room correction system was setting at 8kHz apparently went a long way toward fixing this. I've also found that it makes movies sound closer to what I'd expect them to sound like in movie theaters with the best sound systems. The Pioneer's room correction system is apparently setting for a perfectly flat response including room reflections, and I'm learning that it may be best to exclude the room reflections at higher frequencies. Fortunately the Pioneer lets me adjust most of the room correction criteria myself. My purpose of posting about it here was in case it might help anyone else.
I'm not planning on replacing my receiver anytime soon, unless I discover it is a real problem. I tried to compare it with Yamaha, Onkyo, (and I believe Denon, 4 brands total) before purchasing. The demo setup at the two Best Buy/Magnolias were certainly not the best, but the Yamaha and the Pioneer sounded the best. In retrospect, knowing what I know now, I might have given more consideration to Denon. I'd probably give less consideration to Pioneer now since they've been purchased by Onkyo. Based on the questions I've seen come up in the Pioneer forums, I've found the new manuals to be rather lacking. I think Onkyo is the only option left for a THX receiver now. My next upgrade will probably be a video display.
The S150s are extremely clear and revealing. Dialog is as clear as I've heard it anywhere on any system or speakers, including theaters. However I often find myself listening to details of the orchestral music in movies. Maybe I've just learned to listen better, but it seems like the M&Ks have made it considerably easier to listen to specific subtle details and layers of movie soundtracks. I did have a few frustrations with the grills on the subwoofers for a while, but those have been fixed now and they sure integrate wonderfully with the S150s.