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ilya zaslavsky
mono vs stereo
on Aug 24, 2012 at 6:03:53 am

Hi all,

I have a question on whether it matters if I have mono and stereo sound mixed in timeline for a good quality film that I want to send to festivals.

I realized that only after I have both the film and trailer finished. This is the trailer:

As soon as I put up the trailer some of my friends who understand sound better than me (but can not answer this question properly) told me that part of my sound is recorded mono while other is stereo. I looked it up in the FC timeline and indeed about a quarter of the carefully made sound design is in mono. I have not realized this. I just naively chose the cleanest recordings and worked with them, thinking that only proper volume and clean sounds matter.

I do have most of that quarter also recorded in stereo although it seems that the sound is in some instances a bit more dull or even worse than mono.

My question is: does it matter for festivals? Would this be considered a big and rude unprofessional mistake and I should re-do all the bits using stereo?

If the answer is yes, what exactly is the best way to overcome the problem? Can I put stereo files to correspond mono ones underneath them in the timeline and just work on the volume (that would save time) or mixing mono and stereo is even worse? Or should I completely remove all monos and ensure that everything is stereo. Also someone suggested a third way - that I somehow should turn mono into stereo by doubling ("out parallel") recordings.

Would appreciate any tips on this issue.



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Rafael Amador
Re: mono vs stereo
on Aug 24, 2012 at 11:28:54 am

I'm listening on a laptop, and anyway I'm very bad for audio, but what i hear is that the sound haven't been panned in a few places.
- The music in the first 20 seconds is all in the left.
- The lady laughing in the 25", the laugh sounds in the left, while she is in the right side of the screen. In real life you would hear more through your right ear.
- The guy in the 1'30". seems that sound stars centered, then go to the left, then pan to the right. While the guy is always in the left side of the screen.
- The lady in the 1'57", the same. The audio needs to be panned to the right side, where she is.
- The final music is all in the left too.

[ilya zaslavsky] "My question is: does it matter for festivals? Would this be considered a big and rude unprofessional mistake and I should re-do all the bits using stereo? "
Is not about being festivals or being professional or not. Is because many times the audio is more important than the picture, because is what builds the ambience, atmosphere or how you want to call it, and because our ears are more sensible than our eyes. I mean, is more easy to deceive our eyes than our eyes. In fact a film is just a sequence of still. The movement is created by our eyes and our brain. Audio has a different nature, and you need the real thing coming out of your loudspeakers.

That film look really good, and deserves a good sound.

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Bret Williams
Re: mono vs stereo
on Aug 25, 2012 at 5:08:27 am

Ditto. The trailer IS stereo. You say some clips sound better in mono. Which doesn't make any sense unless you have some recordings with out of phase issues, and possibly you're monitoring your setup in mono so you don't notice the incorrect panning. But If you're monitoring in mono you'd definitely hear the phase issues as sound that just seems to not exist, or very muddy. The two sounds cancel each other out. But when hearing in stereo they're panned to different speakers and you don't hear the problem. Perhaps you had some issues with the dialog, so you deleted one of the audio tracks which alleviates the problem. You then need to pan the remaining track to center.

I hear what Rafael is saying about guy who's sound is moving all over. I think both mics are open, and when he goes in close to the other guy, the other guys mic is picking him up. In that circumstance, I'd just pan both tracks to center, or kill the other guys mic while he isn't talking so you can only use the one guys mic and pan it slightly left.

It is also possible that you're monitoring in stereo, but some stuff is out of phase and is panned to center. If many of the audio tracks were recorded with 2 miss, and you're using both in the mix, but one was out of phase, it'll cancel the other out. But if one's a boom and ones a lav or camera mic then it wouldn't totally cancel each other out. So if those tracks are dual mono or panned to center, then it'd be the equivalent of monitoring in mono. I could see why you'd delete one track of the two (thinking you're not working in stereo by doing so) and stating that you thought it sounded better in mono. And it probably did. Just pan the remaining track to center.

I don't know why you have some music tracks only coming out of the left. Find their other channel and put it back or pan the one track to center.

This is all pretty 101 stuff. I'm surprised you're hazy on the mono stereo thing because the film looks pretty professional and the trailer is well done. Except for the two guys in the street from high angle, the grading looks pretty nice too. The two guys just look kinda washed out. Nice piece.

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ilya zaslavsky
Re: mono vs stereo
on Aug 25, 2012 at 5:10:10 am

Thanks, Rafael, for looking carefully at the sound issues with pan and for comments.

I will work on pans (still searching for guides on that, but I will scan through youtube and google more).

But what about stereo and mono? Should I:

1) substitute all stereo instead of mono even if the sound quality a bit more dull and slightly noisier?
2) or keep mono, but just double it from one track to two and pan one to the right and one to the left
3) or insert stereo underneath mono track and combine the two while ensuring that loudness does not go too much up?

What is the best and accepted way professional way in such case?


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Rafael Amador
Re: mono vs stereo
on Aug 26, 2012 at 7:15:36 am

[ilya zaslavsky] "I will work on pans (still searching for guides on that,"
Understanding panning is not complicated.
Panning have to give you the physical position of the actors in the scene, or of whatever other source of sound like a car, or an instrument in a band.

Look at this scene where the couple is talking in a room:

Think that the audience of the movie is sitting where the camera is.
In real life, when the lady in the left is speaking you would listen her through both of your ears, but a bit louder through your left ear, because is closer to your left ear.So when you play the movie, her voice should come from both loudspeakers, but have more "presence" in the left than in the right.
So if you have recorded the scene with only one microphone (you have one mono channel) you have to pan the audio a little to the left when she speak. WITH YOUR EYES CLOSED you have to "see" that she is in the left and he is in the right side.
If she was walking from the left to the right of the room, you'd need to keyframe the pan from left to right while she is walking.

[: zaslavsky] "But what about stereo and mono? Should I:"
Wihtout knowing what you have on your time-line i really don't dare to tell you what to do.
BTW, open your Sequence Setting and make sure that is ser to "Stereo downmix'.

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ilya zaslavsky
Re: mono vs stereo
on Aug 28, 2012 at 5:44:55 am

Thanks Rafael, for all the advice I will soon put up a better version of the trailer thanks to what you and other professionals noticed here. However, I am still perplexed with one choice:

[Rafael Amador] "So if you have recorded the scene with only one microphone (you have one mono channel) you have to pan the audio a little to the left when she speak."

But even with mono there are two ways how to make it sound a bit more to the left. The mono is still taking two tracks in my timeline - audio 1 and audio 2. By default A1 stands at -1 while A2 stands at 1.

So if I want it to sound more from the left channel I need first to press opt L and disconnect the two tracks from each other. Then I have to options.

I can either put both at say -0.6 or I can put first at say -0.9 and the second at say 0.2 so that the some voice is coming from the right channel. And I am not sure what's the best way. In a way I can't understand if these two ways are pretty much the same thing, and how much secondary should the right channel sound.

WHat also confuses me if what this scene was recorded in stereo - if I put 0.2 on the second track of the stereo it would almost create a mono out of it. Thus if I want the stereo to sound to the left and at the same time stay as stereo I then have to always put both A1 and A2 at say above -0.5? (thus they are both negative and both stereo enough). But in this way right channel might end up almost silent.

Thirdly what confuses me is that some of the stereo that I have of the timeline is very unequal: A1 is full of sounds, while A2 is much quitter, dull, as if it was recorded through some cloth. In some cases one of the tracks in audio (when separated from the other) is almost silent. Thus I am left with one stereo track as if it is mono. In this case anything that takes place in the centre of the scene thus forces me to pan it close to 0, which in turn makes my one stereo track to become mono track.

I wished there was some numeric guidance on how much to the left is for A1 and for A2 when it is mono with two tracks, stereo with two tracks and stereo with virtually one loud track. I do this through headphones, but am worried that in the bid movie theater it will sound like jumping from left to right or from completely mono to almost full stereo.

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Michael Gissing
Re: mono vs stereo
on Aug 29, 2012 at 4:00:09 am

It is highly unusual to record in stereo. It is likely that you have two channels, perhaps two radio mics or a radio and boom. This is not stereo but dual mono. The signals are not meant to make a stereo image.

Unlink the audio and pan all dialog to the center. Choose which is best and fade down the other channel or mix between if it is two radio mics and two people talking. Dialog is almost always panned centre in mixing for cinema or TV unless it is off screen or the is a reason to pan like someone moving off screen.

If you have a break stereo sound then it is good to have it linked and panned but I suspect you Don,t have that so each track should be unlinked so you can control levels individually and pan as required.

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ilya zaslavsky
Re: mono vs stereo
on Aug 31, 2012 at 4:50:48 pm


I carefully followed all comments from all who kindly participated in this thread. Can you please look if the new soundtrack of the trailer no longer has any more grave mistakes?:

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