Quote Originally Posted by Gov
Curtis,

I am really interested in your opinion crossing the Sierra's at 80hz (small) with a sub for music and movies. I am wondering just how much better (if at all) they are compared to the 340SE's in that roll.
Agreed, it would be very interesting indeed. Theoretically, they should still sound cleaner, of course, but the question is whether their dynamics will be noticeably superior in this common configuration. Generally speaking, crossing over at a higher frequency may seem like a waste of the Sierra-1's frequency range, but even much larger floor-standing speakers can benefit from the reduced load.

By the way, yet another issue concerning the selection of an ideal crossover point for 5.1 audio is the interaction between the bass in the main channels and the LFE channel with respect to phase. Any time different filters are used on multiple channels to derive a single combined channel (i.e. the subwoofer pre-out), there is a strong possibility of phase cancellation due to all of the disparate phase shifting going on. This issue is well known in the industry, and mixers will take it into consideration when they determine what to put in the LFE channel, but as far as I'm aware, they only monitor the end result when crossed over at 80 Hz (the de facto industry standard). Crossing over at any other frequency can result in some unpredictable amount of bass cancellation, which while probably not severe or even noticeable in most cases, is still less than ideal. And crossing over at more than one frequency--particularly within the front stage--can introduce even more arbitrary cancellation at the electronic level.