THX soundtrack in Vegas?

pwschulz wrote on 10/31/2003, 1:49 PM
Hi

I've been searhing around for information on how to make a 5.1 surround soundtrack (AC3) that complies with the THX standard. Does anybody know, or have a reference to information on the requirements for making THX sound? Does Dolby Surround EX mode have something to do with it?

Here are some observations I've made:

With my Logitech Z-680 (connected to a Terretec AWS88MT), I adjusted the balance according to a THX Audio test on a StarWars DVD. The THX-logo/demonstration at the beginning, the movie-music, sound-effects etc sounds quite nice and balanced from the DVD after THX "calibration". I recognize that the balance is similar to that in a THX movie theater. However, when I keep this settings and play some other source like from MediaPlayer or previewing music/sounds in Vegas, the sub-bass gets extremely loud. For THX-calibration, I can keep the sub-bass centered (at 10/20), but for other uses it needs to be lowered all the way to 1/20 to sound relatively normal...

In an attempt to make it work in Vegas, I used EQ to cut off frequencies below ~200Hz on a surround-track (L,R,C,Ls,Rs). Then I duplicated the track to create a separate LFE-track on which the volume is lowered to be in balance with the rest. This works quite OK, and sounds natural. However, previewing (no EQ) is still like listening to a thunderstorm (quite unpleasant). So, if this is a sollution, with the sub-bass set at a much lower level, I guess the sound will be out of balance when played on a non-THX set like stereo-speakers on a TV, or ordinary stereo speakers... Doesn't make sense ?

Conclusion:
I'm probable on the wrong track here, and quite confused with this issue... I'd like to hear some thoughs/insights from others. How can I be "THX-compatible" and still sound good for others?

regards,
Per-Willy

Comments

Cold wrote on 11/1/2003, 12:50 PM
http://www.dolby.com/tech/L.mn.0002.5.1Guide.s.pdf

Start here for some basics on surround setup, then do some searching for thx specs. This is a monstrous topic.
pwschulz wrote on 11/1/2003, 1:45 PM
Thanks a lot!
This seems to explain pretty much of the things I was looking for, and the THX specs are probable available through www.thx.com somehow... if I actaully need them after all.

PW