Originally Posted by 1983weatherby
Using ascend 170s for mains and 200's for surrounds.
Room is a converted garage with carpet, drapes on my screen wall and completely on the right hand wall. I have a couch and a sitting chair in the room. If anything my garage has more dampening than my living room setup.
This is guess work, but hey...
Looking (closely) at the 2nd chart on the link below there is a broad peak in horizontal off axis response at 30 and 60 degrees (blue and red lines) from 2kHz to 5kHz. There is an even bigger off axis broad peak in the vertical response at 15 degrees (blue line) from 3kHz to 6Hz. In each axis there is a broad drop in response before the peak. Theses off axis responses are reflected from the side walls, ceiling and floors and then reach our ears.
Humans are most sensitive to sound in the approximately 2kHz to 5kHz range. The unpleasant sound is likely from the reflected broad peaks, especially when the ears (and brain,) compare the broad peak to the broad drop before the peak. Human are more sensitive to broad peaks and depressions than sharp peaks and depressions.
Off axis response such as this is very typical of two way speakers. The dispersion of the woofer narrows with higher frequencies hence the drop in output off axis, once the tweeter takes over the dispersion widens, just as seen in the performance graphs. The crossover frequency doesn't seem to be specified in the specifications. The higher the crossover the worse this off axis response becomes. It's physics based on the size of the drivers and frequencies those drivers are producing. .
This sort of response issue is very typical of two way speakers, especially if they have 1st or 2nd order crossovers (which lowers cost) that force the crossover frequency higher to protect the tweeter. Peaks and valleys in off axis response, with resultant uneven response in reflections, is one the key reasons for dissatisfaction with speakers IMNVHO.
You can likely tame the unpleasant sound by putting sound absorption at least on the side walls at the point where the sound reflects. 4" fiberglass or equivalent would be best. If the garage has a low ceiling those reflections are giving problems as well, as is the floor, depending on the existing absorption. Much of the cost of of more expensive speakers should be for for three way (tweeter, midrange, and woofer) or four way designs, with 4th order crossovers. Absorbing these side reflections has negatives as well, somehow the sound isn't a enveloping. The best approach is the purchase speakers with even on axis and smooth off axis response, but these cost money, and many more expensive speakers are still poorly designed in this area. The absorption of side, and up and down reflections, then becomes unnecessary.