where do you cross over your ht setup

Exertfluffer, thanks so much for the info. Today I tried running the LFE straight from the processor to the Sub. Which, in effect, bypassed the external controls/crossover. It didnt make any difference. But, when I choose, and I usually dont, to run my Sub when I listen to 2 channel bypass, I will need the Xover since my Processor only outputs a full range Subout (in that mode).

Sheesh. You guys thought i was long-winded ???

Personally, i disagree with a LOT of what Exertfluffer has stated concerning full range mains, surrounds and powered subs. "Most" commercially built powered subs perform less than optimally for multiple reasons and should be avoided. They are nothing more than a compromise and a convenience for those that aren't willing to do things "right" and / or want to keep things simple / are on a budget. There are exceptions to this rule, but for what these "exceptional" powered subwoofers cost, you could easily buy a passive sub, active crossover and a better quality amp. Most manufacturers charge a LOT for that "convenience factor", especially when maintaining high levels of quality through-out the entire design.

As to some of the other conversations here, my theory is that one should buy speakers that are suited for the task at hand. That is, IF one wants to do things "most correct" or "optimally". While i realize that most folks don't have the space for this and have to compromise / blend their 2 channel & HT systems together, I didn't do that and don't recommend it if at all possible.

I think that Vedric and i are on the same page. That is, my mains are down about 3 dB's in the low 20 Hz range. My surrounds make it down to the high 20 Hz range due to slightly smaller woofers and a slightly smaller cabinet. I mention this because El brings up a very valid point, but one that doesn't apply to my system. That is, since much of what we are hearing is voice reproduction in movies, the most important part of sound reproduction for an HT system would be the midrange. If the woofer is doing double duty as the lower and / or upper midrange, having it try to reproduce deep bass will surely "muddle things up". That is why i bought and run four-way speakers i.e. woofers, lower midrange, upper midrange, tweeter for the mains and surrounds.

In a design such as what i'm using, all the bass that requires any type of excursion is handled by dual woofers. Using this approach, the other drivers can do their thing over a narrower bandwidth. Not only does this reduce the required excursion from each of the other drivers, it lowers distortion, increases power handling, improves transient response and raises the max spl of the system. It is a "win-win" situation and there is no loss of resolution due to having the mains cover the full bandwidth.

Then again, every situation is different and you have to build / design for that installation and / or work with what you already have. Given that most people think of HT as being BIG "booms" and high spl tire screeching, the market has been flooded with highly efficient, low cost products that measure and perform poorly but sound "exciting". If that is what one is looking for, a cheap but effective system can be easily built for not that much money. Personally, i wouldn't take that approach, but there are tons of people out there that are doing just that. Sean
>

Sean,
LOL, but as I was reading that post I was thinking it was you (i didn't look at the header). I've always believed you should set the cross a full octave above the -3dB point of your speakers, to avoid just such a 'hole' in the LF response. Of course, this is still just a crude rule of thumb, and more precise (actual) measurement of the in-room response and tweaking would be better. And also, of course, this esults in the sub operating up in a fairly elevated (and localizable) frequency range. Which makes another argument for mains and sats that can go flat to 40Hz or better (as you've done).
Tim

I run full range mains (F3 30Hz, F6 20Hz, Q=.5) with an 80 Hz second order high-pass for excursion control, but plan on switching to 40 Hz 4th order.

Sealed box excursion increases 4X with each octave lower, dipoles 8X - so although my (half-space, semi-anechoic) excursion limited main speaker output is 118dB @ 80Hz and 100dB @ 40Hz it's just 82dB @ 20Hz.

Reference level home theater playback calls for 105dB regardless of frequency.

Drew when you make the switch from 80hz 2nd order to 40hz 4th order you will absolutely notice a difference in directionality of your mains. Any panned image utilizing each channel from 80hz and lower will create a more palpable image. A horse riding in soft soil from R to L for example.

Depending on your previous subwoofer setup you may or may not be able to recognize this right away. If for example you had a pair of subwoofers in each front corner both working off the single LFE channel you would be used to a more frontal diffuse sound in this region. The actual change will be more difficult to locate.

If you were using a single subwoofer operating in a corner the difference will be obvious if your mains are up to the task. You are moving in the right direction providing your room doesnt freak out on you!

Eq'ing a sub properly between mains and surrounds remains a challenge in all but the most perfect rooms/systems but it seems most manufacturers are "getting it". Velodyne's digital drive subs as yet another eq'able example.

If its mixed from the right rear any attempt to reconstruct the signal from the right rear is one more step toward sonic perfection. This cannot disputed.

PS: Im glad that Sean guy somewhat agreed with some of what I've said! I would hate to have one as long winded as him as an enemy! Just kidding Sean! :)