[brucek]

Any crossover that I would apply would come either from the receiver (if it's applying any crossover at all; something I still need to find out) or from within the software passing the digital streams to the soundcard.

I just can't see that there would be any other reasonable way to bass manage your speakers than have the receiver do it. Just because you're using an HTPC as a source should be irrelevant.

I think you're right though, I need to go from the soundcard to the sub directly.

I have to disagree. Feed the receiver and engage the standard 80hz crossover.

How would I EQ that? Would setting my maximum sweep frequency to be the same as the upper limit of an LFE channel work? Is there even a standard frequency range for LFE channels? I sense a trip to google coming up.

The LFE channel "spec" allows for frequencies up to 120H. But, even though the LFE does indeed extend out to 120Hz in the Dolby spec, my understanding is that the sound engineers roll that off themselves to integrate it more smoothly into the standard 80Hz LPF (low pass filter) crossover provided by all home processors.

The actual spec'd information when given to the sound engineer goes all the way to 120Hz and then is digitally cut off. This would be horrible to listen to if sent to a sub, so I guess it's their creativity to roll it off (and a smart move).

Since the 'small setting' redirected bass is normally rolled off from 80Hz (when that's the crossover you choose) at 24dB per octave, I suspect that the LFE channel is given similar roll off characteristics.

At 24dB per octave, the amount of signal left at 120Hz is quite weak. Myself, I wouldn't be concerned about any differences in setup because of the LFE channel.

brucek