where do you cross over your ht setup

I'd like to add that in addition to the importance of room acoustics/speaker placement discussed above, it is also extremely important to avoid "double filtering" the audio signals to your active sub. The results can be very unpredictable if you feed a sub's filtered line-level input from a processor's filtered LFE output. (Nearly ALL receivers/processor's LFE outputs are filtered). This can either cause the dreaded bass "suckout" or "boom" even if the sub is positioned properly in the room. This is especially problematic when you set the active sub's crossover frequency close to the frequency setting in the processor. The interaction of the two filters, which may have very different characteristics (different slope, etc.), in the signal path can wreak havoc with the sound.

Many higher-quality subs offer an unfiltered line-level input for exactly this reason. It's usually labeled something like "LFE-in" or similar. Or there may be a "bypass" toggle switch you can set to bypass the sub's built-in crossover.

If your sub lacks the unfiltered input and you are going to use your processor to set the crossover point for LFE, you should turn the sub's crossover as high as it will go.

My $.02 ;)

John Z, I do exactly what you say not to, and I am not 100% satisfied with how my Sub sounds. Although 100% satisfied with audio is an oxymoron, especially with Subs. Anywho, can you or someone else, explain the technical reason the two filters will interact poorly.

I am going to tinker with cabling tonight and I intend to try your recommendations, but I would like a technical foundation on which to ponder. Thanks in advance.

Yeah you can run into problems if you stack crossovers or interstect them. It's often best to set the crossover on the sub as high as possible if you don't have a bypass, and are using the processors internal crossover. If you like the sound you are hearing "distortion", then there you are!
If it ain't broke, don't fix it!
Still, there are numberous articles by industry professionals that say you shouldn't do what you're doing in general. Still, tinkering and tweeking is ultimatly where it's at, as system set ups and equipment matching will have a great deal to do with all this. Still, what I find is that the single greatest areas or down falls for most is both speaker placment, seating placment, and system set up paramaters and tweeking!...not to mention other room acoustics problems. All that is followed by poor gear selection for appropriate needs being a distant last!
Good luck

For lack of a better word, I fiddled around with the setup last night. Changing around the settings for large and small, Xovers (5hz increments), and the Sub Xover bypass.

The jury is out on HT, but, the bass did improve with multi-channel music when I, set only the rear speakers to "small," selected 80hz as the Xover point, and bypassed the Subs internal Xover.

I am still curious about the technicalities. I would imagine that like most everything else in audio, less is more. A signal running through two Xovers is unnecessary and doubles the potential to degrade the sound quality. Not to mention slope differential (db per octave) or overlap.

Thanks for the tips.

Distortion...Every crossover except 6 dB/octive is a cascade of several filters. The common 24dB/octive slope used with electronic crossovers is four stages. Guess how you make a 48 dB/octive X/O.

There is nothing evil about "stacking" two crossovers, however the very steep crossover may not be desirable, and if the two X/O are set to different frequencies things could get messy.