AC3 5.0 to 5.1 ?

kenma wrote on 9/27/2003, 5:00 PM

Hello,
I have an ac3 where the LFE-Channel is missing. Is it possible to generate a LFE-Channel from the other five channels ? How does one has to do that ? I'm using Vegas4 with 5.1 Surround Plug-In.
regards
Ken

Comments

bgc wrote on 9/27/2003, 5:36 PM

One simple technique is to just render another track which contains just the low frequencies of the other 5 channels. You can do this by using a low-pass filter with a cut-off of about 120Hz. You can also cut, boost or mix this LFE track to your liking.
B.

kenma wrote on 9/29/2003, 9:13 AM

I've seen, that vegas has an low-pass-filter, when setting up a new project in surround-mode, but I'm not getting through, how it has to be used, the manual is not very handy to that, or did I misread something ? Is it possible to generate a new LFE-channel out of the other channels with vegas ? what are the steps to do it or to use the low-pass-filter in vegas ?

My first test to do so was not successful. That's what I did:

- loaded all mono-wavs (C, FL, FR, SL and SR) and panned to their surround-position
- created also a track for LFE, panned to LFE but loaded nothing to this track, because I want to let vegas generate it :D
- went to "render as...", choosed the 5.1 template and vegas started to calculate the new ac3
- when finished, I extracted the wavs from the newly generated ac3-file again, and opened them into soundforge, but there is no data in the lfe-wav again, but in the others!

What am I doing wrong ? How is it possible to generate the LFE-channel ?

regards
Ken