where do you cross over your ht setup

Distortion- I'm glad to hear you heard a difference trying it this way. It never hurts to experiment!

It's just good advice I wanted to pass along that I came across on Polk Audio's website. Although I do not use Polk speakers or a Polk Sub, the information provided there applies to any speaker setup. In fact, Polk asserts that connecting your active sub via line-level cables can often sound worse than a speaker-level connection unless you do it right. This may sound counterintuitive, but his reasoning is that the speaker-level connection will avoid the filtered LFE output of most pre/pros and that any cable effects introduced are much less of a degradation to the audio signal than the double filtering of multiple crossovers in the signal path. Getting a good "blend" between your sub and mains is only made more difficult if the crossover point for LFE output is fixed at something like 80 or 100hz, as in many mid-level A/V receivers.

You can find the info at www.polkaudio.com, click on "Home Audio" then "Setting up a home theater system" under the FAQ's & Advice section. You can find a fairly detailed explanation of why it's bad to "stack" filters there as well. Check it out.. it's a good read even for seasoned audiophiles.

In responding to "john Z's" comments regarding Polks info, and the general opinion on running "line level" vs. "speaker level" needs some more explanation I think, as it's a very important consideration.
First, I think that connecting your active sub via "speaker level connection" in a purely music system(probably mostly 2 channel), can often work quite well and, I think, is often a viable consideration for best results! You can often avoid some of the "POTENTIAL" trouble situations you may encounter this way, some of which where discussed previously by John Z. I ran my high end 2 channel monitor set up that way for a very long time, using my SF Minima Amators driven full range (only play down to about 45 hz+/-) with a 2 channel set up, while using a powered sub connected "speaker level", thus using the subs own internal cross over to blend the sat' with the sub....and the results were tremendous for my AVERAGE music listening needs! The blend sounded excellent, no phase issues, or weird anomolies, etc.
The only down side to that system set up, was that very dynamically challenging music material, like Techno, rap(if you listen), heavy percussion, some new-world, hard rock, giant scale orchestral, etc, will distort the woofers in your small speakers this way!...as the mains are being driven full range, and most can't handle(as I mentioned in all the other posts I had) truely deep demanding bass info so well!(refering to even most full range passive speaker monitors). REally, ALL THE DEEP BASS INFO needs to be handled by the POWERED BASS WOOFER! That's been my extensive experience anyway. Heck, even the older NHT VT2 towerers, bigger Klipsch, and higher end Dunlavy's that were known for excellent bass on their own can't handle some stuff, MOST ESPECIALLY DD/DTS movie stuff on their own!...you gottta get the powered subs involved somehow.
Anyway, without going "there" to much, back to my point...
..So really, the "speaker level connection" to your powered sub, letting the mains run full range, and crossing over the sub internally can often work in many situations that some might encounter. STILL, seing that were talking about most people here who are using 5.1/7.1 surround sound systems, involving "summing the bass" into the sub(for one issue), and/or letting the mains handle the bass, and or with the sub, this "passive speaker connnection" posses some problems.
For instance, when you're "summing your 5.1(or better) bass info, in one case, into your "main L/R speakers", and connecting a sub via "speaker level" (connected to your main speakers, or amp's binding posts), thus making the sub play the same bass info that's being mixed into your main L/R's, you're making your mains play FULL RANGE BASS INFO which they really can't properly handle!..even if the powered sub is assisting with the demanding bass dubties for DD/DTS movie applications! Which I stated earlier, becomes a much more appropriately apt job for the POWERED SUB WOOFER! So, in this situation, the mains are really straining(also straining most peoples amps, especially receiver's amp sections, causing dynamic lose throughout the system) trying to reproduce very demanding bass info, not to mention distorting! So in this set up, where the mains are driving full range "in paralell" with the powered sub(even though crossed over in the sub), you will encounter rather slow, muddy, mushy, distorted, less dynamic, unrefined, sloppy, and just plain "Flatt sounding" bass response from your other wise "over taxed" bass woofers in your main speakers most often!(this would be "less worse" with monster main speakers with high efficiency and large large woofers built in however). In most peoples standard audiophile speaker rigs, again, taking the more demanding and challenging bass info OFF OF YOUR MAIN SPEAKERS has far too many benefits to your entire system!...not just sonically from your mains, but also dyanamically freeing up your main multi channel amp to more aptly reproduce what it does best, and that's reproduce less taxing upper bass on up!!!
Case in point, I can remember running many many 5.1 systems with the mains being run "full range" (sub via line level filling in the bottom), letting a receiver handle the amplification for the mains. with some of the more demanding bass soundtracs from some of thes movies out there, as well as "strong driving bass heavy music", like techno, the receivers amps will not only sound "flat" and "strained" throughout the system, but will get so hot and overworked that you can "shut down the system" or, at the very least have heavily compressed dynamics from the speakers! In this case, if you must run your mains "full range", you have to AT THE VERY LEAST run separates! Receivers simply can't handle this so well in general!..even the big flag ships! I know, I've experimented with the Big Denon's, Yamaha's, even Marantz's, etc(Actually, the B&K handled this the best).
So, back on track here...for PROPER DYNAMIC DISTRIBUTION, dynamics of sound, lack of strain and distortion, and maximum efficiency, you really need to get the bass off your main speakers(and center/rear sat's), and let the bass woofer(s) handle the bass and deep bass! That means running the sub "line level", which mean through the LFE mostly!(in the case of a 5.1 or better system, using a receiver or pre/pro).
Breifly bouncing back to my point about 2 channel set up driving main speakers and a powerd sub in paralell via "speaker level" connection, again when you play demanding dynamiic music through this set up, you really can't get the dyanmic potential in this "passive system" like you can when you're either doing a filtered sub/sat set up or, better, an "active" speaker system!(having all active speakers, with active sub possibly!). So there are trade offs, and each persons needs are different. For me, I sometimes like to listen to the "harder/heavier stuff"!
But for most peoples 5.1/7.1 sytem, the best way is still going to be utilizing PROPER BASS MANAGEMENT and a powered sub(s) connected via "line level" or LFE connection! The dynanmic range potential here is not going to be bested any other way. The only exceptions to this as being the best way, is when your using much more efficient main speakers(or center/rears even) like "powered towers"(i.e, Def Tech's, etc), truely active large full range speakers(like Avlar's, maybe even ATC's, and similar), or very high senstivity large pro audio/horn speakers that play over 100db/watt sensitivity with 15" woofers! OTher than that, most people using standard home audio passive floor standing and mini monitors are getting infinitely better dynamic capabilities and range by effectively "bi-amping" their system, using a crossed over sub/sat set up!!!..that's just the way it is. THX knows this, and all the top HT guy's know this! The audiophile purists might argue against these comments, but then they most all have rather "limited dynamic", weaker sounding sytems that won't hange with the better more apt dynamic systems set up for proper HT playback! I know, I've heard hundreds, maybe even over 1000 of the systems most audiophiles have running in 2 channel over the years! They watch movies connected via analog through their 2 channel high end rigs, and they like it that way just fine! And that's great I think. But those sysetms will never match the dynamic range of a truely proper HT set up!
Peace...

Exertfluffer- I agree with your points above and I have very much enjoyed your posts. I just mentioned the speaker-level connection scenario in my post to illustrate a point that Polk makes that there are often several options available for working around "double filtering" and connecting an active sub to a system and the LFE-OUT is not ALWAYS the best choice in certain situations. Certain connection options (like speaker-level) that are seldom considered by many people can often work very well depending on your particular type of speakers, etc. I agree that it's not necessarily the BEST choice for HT in the assumed 5.1 system, but as we both have both stated above (either literally or inferred), it can pay BIG dividends if you take the time to experiment and learn exactly what you are dealing with within your own system.

I fully agree with your recommendations as they pertain specifically to 5.1 discreet HT. However, the Polk recommendations I paraphrased above were taken somewhat out of context and were a bit generalized. The Polk website covers many scenarios including using a sub just for 2-channel music, sub-sat systems vs. full range mains+sub, etc. but I did not want to repeat the whole article word-for-word in my post.

But I do think it's important for people to be aware of the problems that cascading filters can cause(that hard-to-nail-down "hump" or "hole" in the mid-bass, for example) and that often people aren't even aware that this MAY be the culprit (or a contibuting factor) in their HT setups.. And it was not being mentioned prior to my post.

Cheers! JZ

I would like to add a few responses to exertfluffer. Some of what I said you responded to out of context. No worries and Im not going to troll through what you've said to quote, your posts are huge! :)

I somewhat resent your comments about 2ch. audiophile setup being somehow outdated. Acoustics is acoustics. Building a HT around quality 2ch. setups has produced the finest results in three rooms ive been involved in (one being my own). In fact I believe its the only way for true high performance HT. That is, performance closest to the source (origonal mix). Sure this can be difficult but its not impossible. My point is: people with a quality 2ch setup are already ahead of the game and likely dont need to crossover their mains so damn high!

With a good room, a little work, and proper surround speaker selection you might be suprised at how much lower you can cross your surrounds to! Again, its ALL dependant on SO many factors. However, trying to utilize every last little bit of linear response out of each speaker is worth the effort in my experience. This effort will also teach one much about his own system and acoustics in general.

Dont forget why surround sound is so fun to begin with. Instead of directional imaging taking place more or less within the boundaries of 2 speakers, with surround this directionality can now wrap around us and even hover above our heads. It can be outstanding but every octave cutoff from each channel is sound that no longer contributes properly to this illusion.

I would remind you also that THX standards were NOT designed with HT in mind. These standards were "adapted" to HT as a foolproof way to setup a system. Nothing more, nothing less. Does it work? Sure it does. Is it the best way to setup a HT? Not to these ears.

Vedric...I have cited my reason for a "high" (80-90 Hz)crossover...(to keep the LF that requires large cone excursions out of the mains so that they can better reproduce the rest of the sound). You have recommended 25-35 Hz, suggesting that there is directional information down there. (OK, but that argument does not apply if multiple SW are used).

Question to you...Why do you think that a cone driver mounted in the main enclosure is superior to a similar (perhaps identical) cone driver mounted in a different box?
Six of one: half a dozen of the other.

In my case, where the mains are planar MG1.6, there might be an argument that spatial effects would be different if the higher range of LF eminates from the SW. I have addressed this issue by building three multi driver SW systems into the wall behind the three MG 1.6, so that the SWs "play through" the screens. Believe me, 80-90 Hz works best, even though the MG1.6 measures flat in my room to about 40 Hz.