Editing Film , audio Mono or Stereo?

sp_key wrote on 4/6/2005, 7:56 AM
Dear all,

I am editing my short film in Vegas. My soundtrack includes songs, background sounds - collected on location - and many other samples apart from the dialogues. The source was mono (apart from songs).

I have done many audio mixdowns in the past but never on film and I am a bit confused with stereo vs mono in terms of television or cinema projection. I do not fully understand how 'mono compatibility' is achieved.

a) Is there any difference between a mono track and a stereo (meaning L + R) containing the same information? And eventually, should I duplicate my Mono tracks or should I leave them as they are?

b)Should I treat my audio mix like a normal multitrack recording, paning sounds left and right or should I just find appropriate levels and ignore paning?

Thanks for your time and sorry for any confusion

Comments

BrianStanding wrote on 4/6/2005, 9:35 AM
I haven't done any video to film transfer, so I can't speak to the limitations of the celluloid medium. However, I have done a lot of video projection in a theater setting. So, take my comments with however many grains of salt you wish.

I usually try to keep it simple. Dialog in mono, equally mixed to both channels. Music in stereo, if that's the way you recorded it (or if you recorded it in multiple tracks). I've had O.K. success with simulating stereo by putting different EQ mixes of a mono recording on each channel, but it's a lot of work to get it to sound right.

Leave the fancy keyframed pan effects for any ambient or transitory sounds (a car driving past, for example), if you want to get really fancy. Otherwise, a mono mix seems to work fine.

Keep in mind that many delivery formats, such as AC3, expect a stereo soundtrack. Mixing mono equally to left and right channels usually does the trick for me.

I haven't gotten into the whole 5.1 thing, just because I haven't worked on a project yet that would justify all the complications and time. I'm starting to look at doing some work with local bands, though, so I may get into it soon.

Does this help?
sp_key wrote on 4/8/2005, 6:32 AM
thanks for your help brian.

however, there is a point I might have confused you (probably because I am confused). You say: ''Dialog in mono, equally mixed to both channels'' but what is the difference of having a L+R set containing the same information as you suggested and having a single individual channel? Aren't they both mono?

Sorry for such a basic question, hust one of these fool things I never really understood.

thanks for your time again
B_JM wrote on 4/8/2005, 7:21 AM
it would be considered dual mono ...

stereo btw, started out as 3 chanenls , not two ..

farss wrote on 4/8/2005, 7:52 AM
Exactly. Whether you have two identical stero channels in Vegas or one mono track it's all the same. Film I think today only supports at least two tracks of optical sound, obviously it goes up from there but that's the minimum.
I'd suggest a copy of Jay Rose's book, Audio Postproduction for Digital Video, he covers a lot about mixing for cinema release.
Basically you have to be very careful having anything panned too far to either side. The speakers in cinemas are quite wide apart so someone sitting near the front is likely to not hear the sounds from the speaker on the other side of the screen. Dialogue should always be in the centre, even if the talent is right to one side of the frame.
Also be aware that in a cinema you can have a huge dynamic range.
You should also do a mix for television, for that you need to dramatically reduce the dynamic range.
As you'll be mixing stereo always check your mix in mono, i.e. take the stereo track and switch to 'Combine'. Dual mono can sound just fine on a stereo system or even in a cinema even if the dialgue channels are out of phase. Total disaster when it's broadcast for anyone with only a mono TV.
Bob.