View Full Version : Stereo Recording to Surround Sound?


Peter Moretti
May 26th, 2008, 02:38 AM
I am one of those completely unrealistic persons who believes there's a chance his documentary project will get a theatrical release. Crazy, I know. But please humor me and, if you could, provide some knowledge on surround sound.

I'm recording in mono most of the time b/c a lot of my material is sitdown interviews.

My question is how does a stereo mix get played in a surround sound theater? Does it get remixed for surround sound or is the stero mix used?

My doc has a lot interviews that would not benefit from surround sound, but there is other footage that could benefit from extra spatial control surround sound offers.

THANKS for the help.

Mike Peter Reed
May 26th, 2008, 01:03 PM
You might want to look at a M/S mic which will essentially give you surround compatible production sound (left, right, centre). I've been recording with an Audio Technica BP4029 and am very happy with the spatial image.

Steve Oakley
May 27th, 2008, 12:44 PM
it depends. there are amps that will process stereo into 5.1 by adding some delay and eq to the rear channels to make them sound "like they are behind you". they will also play around with different reverb times. realisitcally you should create your own 5.1 mix, even if its just doubling the music tracks up to directly feed the rears, maybe with some eq. SFX of course work great and there is a lot you can play with.

Chris Hocking
June 7th, 2008, 05:12 AM
Late last year I completed a no budget documentary, that utilised surround sound. Basically, we recorded everything as you normally would (i.e. mono boom, stereo atmos), but then came back to each location and recorded surround atmos (left, right, centre, rear left, rear right). Then using Final Cut Pro, we mixed the film in surround - which was surprisingly easy. Although we could have done it in Soundtrack Pro (as the latest version supports surround panning), just mixing in Final Cut was fine for us, and we achieved some great results. We also played around with some of the surround plugins for Protools LE - but Final Cut Pro was worked fine for us. Logic also supports surround (although I don't own it unfortunately), and there are plenty of solutions out there for PCs. The "All Things Audio" forum has heaps of discussions on both editing solutions for surround, and also microphone discussions. As we were doing essentially a "nature documentary" the surround sound space worked great for us!

The one tip I would say however, is don't get too carried away with the technology! When you're mixing you have a tenancy to want to put audio coming out of the surround speakers all the time (or at least I did!) because it sounds cool. But you really need to keep in mind that audio is just a tool to tell a story - don't put stuff out of the back speakers just for the sake of it!

Also, if you have music in the film, try and get a copy of it as individual tracks. That way you can send elements of the song to the surround speakers (i.e. you might have most of the instruments coming out left and right, and send some of the drum tracks to the rear surrounds for added effect).

As it's not really that difficult to do, I highly recommend giving a surround mix a go! It's a lot of fun, and you can achieve some great results if you put in a bit of time and effort!

However, one thing to keep in mind though is delivery requirements! If you're going to DVD, then your fine - just use Compressor to export out a Dolby Digital file. However, if you're going to tape, whether it be DigiBeta, DVCPro50, HDV, etc. it's a lot more tricky to get the surround tracks on there! We ended up doing a Dolby Pro Logic II version for DVCPro50 distribution. You can do a Dolby E encode if you want to get your surround mix onto something like HDCAM. Basically, just work out what venues you're going to be playing at, and go from there. What I've found in Australia, is that a lot of theatres only play surround sound if you provide your film on FILM. If you give them a digital version (i.e. tape), then they'll generally only support Pro Logic II. However, if you're cool with just DVD - then you're fine. Lots of options - but all important things to think about before you begin, so that you don't run into problems later.

Finally, unless your interviews are taking place in a cave - just leave them on the centre speaker or left + right - don't send dialogue to the surrounds unless it fits in with the vision...

I hope this info is of some help!

Chris!

Gary Nattrass
June 7th, 2008, 05:45 AM
It depends what you mean by surround sound, dolby pro logic is the base level and it kind of works on M/S matrixing with the following signals:

Left=M-S
Centre=M
Right=M+S
Surround=S

5.1 or dolby digital type systems are different and will need a lot more mixing and sorting to enable stereo to be placed correctly.

Of course for docos and most productions the time to sort the surround is in post production as this is where the final image for delivery is decided in both formats, so a sound dub will be required in both cases where stereo and surround fx can be added to enhance the mono location sound.

Roshdi Alkadri
June 9th, 2008, 10:04 PM
someone asked the exact question i had in mind too.

1. So is dolby prologic used only on DVD'S, VHS and broadcast?

2. Basically we are enconding a 5.1 mix into prologic stereo right?

3. Or is Dolby AC-3 the standard for Cinemas?

Either way, wouldnt someone's Film/Doc be mixed when its picked up by the distributer, and they would pay for the sound post and encoding?

Steve Oakley
June 9th, 2008, 10:22 PM
distributer's pay for just about nothing. certainly no sort of finish work whatsoever. its expected you have a finished product. they will spec format & mix type and you deliver.
it will usually be one or two of the following

stereo mix mono safe

split tracks as voice, music, sfx. usually mono

stereo mix minus for dubbing into other languages

as for 5.1, it'll be about the same, stereo safe, and ideally mono safe because you'd really be surprised at how mono still rules the world, like it or not.

you may also have to have seperate cuts if there is anything that might be considered "taboo" in some countries.

Roshdi Alkadri
June 10th, 2008, 05:37 AM
so its pretty good to keep all tracks seperate, dialog, music and effects.
I guess it wouldn't be a good idea to do a surround mix yourself rather than leave the mix to be done later in a better mixing room.