Subwoofer setting

AG, you asked two questions. Fortunately they both have the same answer. Use the crossover point that sounds the best to you. Because it sounds the best to you.

If you have some compulsive bones in your body, get an audio test disk from Stereophile, or Radioshack, or download one off the internet and get a cheap digital sound meter from Radioshack and test where your main speakers roll off in your room. Then set the sub's crossover to cut off at 50Hz and measure the roll off as you go up in frequencies with the sound meter. Then set the sub to 80Hz and do the same thing. See which setting best compliments the actual measured roll off of the speakers and leave it there for now.

Once you have decided on the crossover setting, now use the sound meter and the test disk to calibrate the volume setting on the subwoofer to match the output of your speakers and amplifier as best you can. You will undoubtedly have bumps and valleys at different frequencies in your listening space - but just do the best you can. Try to average output over several frequencies in the center of the subwoofer's range and set the volume level to match the output for the average of several frequencies in the center of the bass band on your main speakers (well above the cutoff).

Now that you know intellectually what cut off should sound best and have calibrated the output levels of the sub and speakers, listen to a few of your favorite bass heavy (not necessarily low bass) pieces of music with the sub set both at both 50Hz and 80Hz and then do what Zieman says above, leave it where it sounds best to you!

I find this method works pretty well, and if the sound I like ends up being "colored" in some way, at least I know how and why. In some systems "flat" sounds GOOD, and in other systems "flat" sounds just, well... FLAT.

If you adopt knownothings approach a good disk is the soundtrack from the movie SNEAKERS, in which a bass drum is struck repeatedly. Down load Sumiko's short sub set up guide from their website , I learned about this CD from it. It is available on Amazon at a reasonable price.

Before auditioning different lo-freq cut-off points (I recommend the 50Hz also) you should find a reasonably intelligent location for the sub. . . . . .
Assuming you have only one sub (best IMO, as long as you can keep the x-over point below 100Hz) AND assuming the sub has no phase adjustment, the best method is to place the sub at your listening position, and then listen to program material from different locations in the room to find the best "final resting place" for the sub ;-) Try listening from these positions:

>Each corner of the room
>Smack between the main speakers
>Different positions along the four walls, but particularly the one behind the speakers.
>Right behind the listening position

One of them should provide the strongest and most seamless response in your room. Place the sub there.
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