Setting Sub Crossover Freq

Potential for lots of overlap, bloat, & slurring with crossover up that high. For comparison try 40hz at both 12db/octave and steeper 24db/octave roll-offs. This may clarify the critical mid-bass and shift the transition between bass drivers into less audible LF region. Less can be more...

I agree, you have to set the crossover point LOWER than the bottom of your regular speaker. Then adjust the integration using the sub's volume control. Don't forget to check the phase of the sub also.

I agree that a sub sounds better out of a corner for music. Corners make for bigger THUMPS, which may be fine for home theater but loses character and texture on music.

If you can hear the sub then it is probably too loud. The integration should be seamless and not noticeable, else it's not set right.

>03-11-10: Ptmconsulting
I agree, you have to set the crossover point LOWER than the bottom of your regular speaker. Then adjust the integration using the sub's volume control. Don't forget to check the phase of the sub also.

I disagree. You have to set the cross-over point high enough that

1) You don't run out of linear excursion on the main speakers. For a non-ported speaker you get 12dB of head room (you can handle 16X more power) with each higher octave. 5-6" drivers in two ways often need 100Hz+ cross-overs to get good performance at reasonable output levels. Obviously this often calls for fourth order slopes and perhaps stereo sub-woofers.

2) You want cross-over points to work around the first SBIR null from the main speaker (where it's 1/4 wave length from the front wall thus causing a null; for instance at 4' you'll get the first null around 70Hz) and room modes stimulated by main speakers and sub-woofers (for instance you might want a 60Hz low-pass on the sub-woofer and 80Hz high-pass on the main speakers to work around resonances in the 70Hz range).

Achieving good integration is a separate issue which may call for options not available in most consumer gear like asymmetric cross-over points. With subs close to main speakers you may benefit from being able to replace the speaker's inherent high-pass function with a different one using a biquad with digital or analog (Linkwitz Transform) realization.

I found going a little lower than the output of my speakers with a little more volume to be much better than the other way around. Mine works best (seamless) out into the room and not in the corner.

For more thoughts, look at

http://www.hometheaterhifi.com/technical-articles/156--miscellaneous-ramblings-on-subwoofer-crossover-frequencies.html

FWIW, there is anecdotal evidence that some receivers still cut off the LFE at the crossover frequency.

http://www.avsforum.com/avs-vb/showthread.php?t=1232328