Question: Hi All,

I have been looking at moving me stereo short doco films with background music to a surround experience. At the moment the design is fairly simple, interview vocals center and music as it comes from the artist (stereo). What can you guys suggest to move the music towards using a full surround experience. I am looking at subtle exposure, not over the top use of the surround stems without compromising the original quality of the music. The sound effects are more natural to mix, so I am not too fussed about them.

I hope that makes sense.

Answer: 
The way I normally start when mixing music for 5.1 (mostly in feature films, but sometimes also in documentaries), is to pull the music slightly towards the center, so that it isn't strictly L-R but more L-R with a little bit of center, so you don't get too much of the "hole in the middle" syndrome. Sometimes I pull it back a little too.

Normally I then apply a hall reverb to the surround speakers, leaving it pretty dry in the front and almost totally wet in the surrounds. This way the music surrounds you without having too much of the direct sound coming from behind you.

I will also send some of the music to the LFE channel.

If I have stereo stems of the music available, I will pan the softer elements more to the back than the percussive elements, and be more selective about which tracks I feed to the LFE channel. If there's no particular bass information in the channel, there is no need to send it to the sub.

The more tracks I have available for mixing, the more specifically I will pan them across the LCR front, for instance narrowing the bass down to the center channel (and LFE of course), or pinpointing the close mics of the orchestra across the screen. I may also use an extra reverb in the front, to give the narrower sounds a bit of spread. I will also narrow the reverb a bit so it isn't strictly LR.

The real advantage when mixing in 5.1 compared to stereo is in my opinion more the enriched clarity and higher fidelity that comes from using more speakers, than it is the fact that you can have sound coming from behind.
From everything I've heard, mixing music into the surrounds is supposedly a big no-no. Same goes for mixing dialogue in the surrounds. Personally, I like mixing music in surround, and depending on the context of the dialogue, I'll mix that in surround as well I'm not one for playing inside the rules or playing it safe unless it's a QC or broadcast spec I have to adhere to. With music you gotta show the people in the back a bit of love too imo. It's not like it's a specific sound effect that will really draw the listeners attention away, so it can be done... but simply done carefully and tastefully, same goes for certain types of dialogue as well. Personally I think surround mixing still plays it a bit too safe. We have this awesome technology and a lot of mixers are still afraid to take chances and push the envelope. Some I might add, are quite amazing at this. If you listen to the surround mix for Inception Gary Rizzo mixed A LOT of music into the surrounds... for that matter it was sometimes only in the surrounds.

When mixing music in surround (which I would typically do in Pro Tools), I'll usually have it in the Quads pulled back around 10-20% from the front and I'll set my divergence to 80% all the way around, that way I'm not hitting the LS and RS too hard, it's not too wide and I'm just giving it a bit of surround space to make it a little more immersive. Sometimes I'll send it to the LFE depending on the scene and what the mix needs. I'm extra careful with that though. I don't ever use verb on the music though. If it's incidental music all bets are off and it depends on the source location of the music in the surround field. In that case I would use verb on the music. On top of that, it also helps clean up a bit of headroom in the L+R and leaves a bit more space for SFX and DX.