Originally Posted by steveting99
Thanks for this, it's greatly appreciated. It should be included as a sticky.
Would like some clarification under item 2. Recommended initial setup when using an AVR. Your write-up mentions that for sealed subs the extension should be set to mid damping before running the room EQ.
In the handout from Brian, he recommends low damping.
I can only assume that Brian's rec is more correct as one can go up through mid to high damping after room EQ.
Mid gives a steeper rolloff than high. That makes it easier for auto-EQ to recognize the low frequency limits of the sub, so it stops boosting at the appropriate frequency. Boosting below the limit can chew up tons of power and hurt the sound. Audyssey is inconsistent about automatically detecting the limit on high, and it's hard to tell when it screws this up. I think Audyssey looks for the -6db point prior to EQ, or something like that. So, that's why Brian recommends running Audyssey at medium, even if you intend to run on high.
When using more sophisticated (less automated) EQ software, you can manually set the low frequency limit. In that case, it's fine to use the setting during EQ that you're actually going to run it at.
Aside from auto-EQ, high gives a slower rolloff, more coherent phase, and less ringing, but it is the least efficient. Low gives a steep rolloff, is much more power efficient, and uses up less driver extension per db of volume. Mid is in-between.
If you have a lot of power relative to your room size, I think high sounds best. If you need more clean power/headroom going to mid/low and/or increasing the high-pass frequency may be best for you. If you need more power, but really want that high setting, try corner loading, near-field placement, and/or adding more subs.