I have my 5.1 setup (some random sony receiver and a tsc/asw-10) and I have the sub volume (on the actual subwoofer) around half way and the receiver has it set at the default 0dB. How exactly can I go about setting it to the correct level? I have my receiver hooked up to my computer, xbox 360 and my tv. Music sounds fine at any level really but movies are entirely different, sometimes the sound is fine other times the bass is too loud and there is an ambient rumble and when a big explosion or something occurs my room will shake.

Any help would be appreciated thanks!

The simplest suggestion would be to turn the subwoofer down a few db through the receivers sub level adjustment when watching movies and then turn it back up to 0 for music if that's the only issues you have right now. Different content especially going from 2 channel music to other audio formats is going to be recorded at different levels so alot of people find they need to tweak between them, once you've found the sweet spot for both it's really no problem and only takes a few seconds to adjust.

If you want to be as accurate as possible about it and your receiver doesn't have any form or auto setup then you can purchase a SPL meter from Radio Shack for < $50 and that will help level match your speakers and sub.

I have my 5.1 setup (some random sony receiver and a tsc/asw-10) and I have the sub volume (on the actual subwoofer) around half way and the receiver has it set at the default 0dB. How exactly can I go about setting it to the correct level? I have my receiver hooked up to my computer, xbox 360 and my tv. Music sounds fine at any level really but movies are entirely different, sometimes the sound is fine other times the bass is too loud and there is an ambient rumble and when a big explosion or something occurs my room will shake.

Any help would be appreciated thanks!

Get a SPL meter (Radio Shack sells one that's a decent starting point) and either the Avia or DVE disc. Use the test tones on the disc to set all of your speakers to read correctly on the SPL meter.

Any other method is guessing.

And for alot more info on the subject:

http://www.avsforum.com/avs-vb/showthread.php?t=1004573

Maybe a THX bass manager or audio limiter to reduce or soften down the large peaks, it also helps with softer low sub bass moments as well.