Settings for 5.1 downmix to stereo

[nicollins]

Can anyone can offer advice on downmixing 5.1 audio to stereo in Apple Compressor? I am mixing some electronic soundtracks in 5.1 format for release on a DVD -- my first experience in this format. My assistant is using Compressor to encode the project. We can't figure out where the settings are for adjusting the stereo downmix for when the DVD will be playing back on a non-5.1 system: the front L-R pair remain in place, but the rear L-R are summed into mono and mixed at a lower level than in the 5.1 version, and the center channel seems to be pumped up higher. We could author a DVD with two versions of each video -- one in 5.1 and one in stereo -- and the user would select which to play, but this seems silly. Don't DVDs of commercial films with 5.1 soundtracks automatically play the stereo downmix when appropriate, and doesn't the mastering engineer have full control over this translation? I had assumed that Compressor was the "professional standard" for encoding video -- should we be using a different software? Thanks!

[tjcasey1]

First, welcome to the world of surround mixing! I love it, and I wish more people were doing it. All those home theater systems are just sitting out there, waiting to pump out the tunes in surround sound....

I use Compressor to create the Dolby soundtrack, leaving the parameters at their default setting (except that I shut off the "film compression", which is just a blunt instrument for dynamic compression).

When I get home I'll take a screen shot of the settings I use and post it here.

If the center channel info seems too loud in the stereo folddown, my guess would be that your center channel monitor is a tad quiet, which is actually causing you to mix the center channel louder. You wouldn't notice this until you heard the folddown or unless you heard the 5.1 mix on a different system. (This diagnosis is taking it for granted you've chosen the correct Dolby preset). Likewise with the surrounds being too quiet - maybe the monitors are too loud in the studio and you're mixing them too quietly.

You should check the mix on a regular home theater setup that you're aurally familiar with and then re-evaluate your studio setup. Studio 5.1 monitor level setting is complicated - it took me about a year to get to the point where what I hear in the studio is what I hear in my home theater system.

And it's not crazy to provide a separate stereo PCM soundtrack on the DVD - I do it. Dolby actually sounds thin and quiet compared to Stereo PCM, so if the music on the DVD is really important, I'd add a stereo track - you can even make it 24 bits.

Also, I'm pretty sure that the stereo downmix is controlled by the particular DVD player, not the mastering engineer.

On a side note, you should look into buying the DTS encoder software. I think it's like $149, and it kicks ass compared to Dolby. Switching between the two on one of my DVDs is like night and day. And most players now have DTS.