How to downmix 6 channels to stereo?
Aug 13, 2009 at 10:28 AM Thread Starter Post #1 of 5

progo

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I ripped my Tchaikovsky DVDA disc to computer and it is a 6-channel beast. I only have two ears, so I thought of downmixing it to stereo. What are the ways to do this? Are there general guidelines for this?

I'm using Linux, and audacity seems to be appropriate but I couldn't catch a downmixing option there. And how to identify the channels?

http://havu.viuhka.fi/kuvat/tchai.png

Second thing: I analyzed the frequence spectrum in Audacity:
http://havu.viuhka.fi/kuvat/tchai-spect.png

The "noise" after 20 kHz is the infamous watermark, am I right?

And if you know some other tools, please do recommend them. Yes... thanks for advice
smily_headphones1.gif
 
Aug 13, 2009 at 11:27 AM Post #2 of 5
Foobar should be able to do this I think by adding the DSP "Convert 5.1 to stereo" while converting. Foobar is Windows only though, but there might be other audio applications which are able to do a similar thing. I don't know of any other free mixing applications which are able to do it though.
 
Aug 13, 2009 at 11:51 AM Post #3 of 5
Actually I got audacity to mix it for me, but the result sounds bad: sounds like a phase issue. Maybe one of the channels misses a millisecond or two; I don't know.
 
Aug 13, 2009 at 2:52 PM Post #4 of 5
I have had good results downmixing some DVDA's to stereo using Audacity.

Typical channel order is Lf - Rf - C - LFE - Ls - Rs and your picture looks like that too, but you could listen C and LFE channels to see if they are really that way.

Then, drop levels of L and R channels 6dB with the level selector on the left, and C and LFE channels 9dB — they are mono channels and we will be mixing them twice at the end so that must be compensated.

Enable in preferences - import/export section the option to use custom mix, and in export dialog mix L / R channels respectively and C and LFE channels to both left and right.

If the end result clips, you'll need to lower the levels even more.

Edit: sox seems to have quite flexible remix effect, that probably could be used too. I remember looking into sox some years ago, but that probably wasn't there at that time. Audacity method is a bit labor intensive, sox would allow scripting to mix all the tracks easily.
 
Aug 13, 2009 at 5:14 PM Post #5 of 5
Thanks!
smily_headphones1.gif

I tested your method and it sure seems to help with the mix. Something still gets highlighted when compared to how the standalone player plays it. But I'll experiment with the gains now.

I know sox by name and it seems to be installed here. However, audacity suffices fine since I only have one DVDA to play with.
 

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