Sarang,
There really is little to add to the preceding excellent posts. Our hearing is very sensitive to timbral coloration in the midrange, not in deep subwoofer bass, so it isn't necessary to use a subwoofer from the same manufacturer as the rest of the speakers. It may be a good idea, since you know the sub designer, at least in Axiom's case, has done extensive double-blind listening tests to his subwoofer and other speakers in the line, however, the notion of timbral coloration in subwoofers is just plain wrong. Just try running a sub by itself without any other speakers and you'll be surprised at what you hear.
I use 80 Hz as the crossover frequency for all my speakers and that works best in my room. But given the huge variation in room setups and room dimensions, and the resulting standing waves (causing bumps and dips in deep bass energy), these "rules" for crossover frequencies are certainly meant to be broken, and experimentation is the key. In my 20 x 13 x 9 ft living room, using 80 Hz with the M80s and an EP500 is ideal. If I lower the crossover frequency to 60 Hz, I get too much deep bass. On the other hand, my Axiom colleague, Ian, who owns Axiom and designs the speakers, uses either 60 Hz or 40 Hz for his M80s in a big cathedral ceiling 2-story living room.
It's going to vary with every setup, but an 80-Hz default crossover frequency for all the speakers is an excellent place to start.
Regards,
Alan
I must admit, after all the experimenting I have done with crossover frequencies, among other things, over the years, when the folks at THX decided that the 80HZ level would be their benchmark, there was "a method to their madness". Like Alan, I agree, in most cases, it just seems to sound the best at that setting.
