Exporting Multiple-mono to stereo interleaved: SUCKS

M

Maor

New member
hey guys,
im using pro tools 10 for mixing and mastering.
im exporting the final mix as multiple-mono file (2 mono files, for L and R, if you dont know..), and importing that into my mastering session.
there is goes from 2 mono tracks, to a stereo master bus, on which i do all the processing. to keep the stereo image looking good, i only use multiple mono inserts, for all of my EQ's compressors, limiters and what not..
everything sounds GREAT!

but in the end, i dont have an option to keep the file a dual mono. the world is working with stereo files- so im bouncing down to stereo interleaved. and it SOUNDS DIFFERENT.
when i import this file to the session, and A/B test with my multiple-mono process, i hear there is a change, for bad, in the stereo image.
it seems like the middle is brought up (unpleaseantly) on the expense of the side information..
everything just comes together to create a mono-ier output.

HOW CAN I SOLVE THIS?
i tried to insert one "stereo" (instead of multi-mono) plugin in the end of the chain, but it doesnt seem to have the same effect.
let me know if there is any way around that...

THANKS
 
If your left and right compressors aren't linked they will tend to push things toward the center and make the stereo image wobble, so it's probably doing exactly the opposite of what you intend. But that's a different issue from what you describe, and if you like the way it sounds who am I to object?

There should be no sonic difference between a single stereo wave file and a pair of mono wave files, all else being equal. How about bouncing stereo and multi-mono versions from the mix project, import them to a new project and comparing those two?
 
maybe some of you misunderstood me:
when i process using multi-mono plugins, of course i do the same exact thing to both L and R channels. otherwise, yea- ill get a weird stereo image, and phase issues perhaps. the reason im doing that, instead of using stereo processing, is because im working with multi-mono files, every stereo plugin, does a little process the sum those 2 mono channels into stereo (interleaved probably)- this changes the balance during the process and i DON'T WANT THAT.

of course, i already A/B testes quite a few times exporting a stereo master and multi-mono master of the same process, and importing them back. there is a noticeable difference in imaging and balance.
i dont think im "over complicating"- im in the business of making things sound good, and exporting a mix or master as stereo interleaved sounds worse.

researching this issue, iv'e come across some people who say they use an outside summing and converting software. that is, export the final master itself as multi-mono, and using a third party software to convert it to stereo interleaved.
I dont know where to start looking though, maybe one of you guys can shed some light on this?
 
Maor said:
....every stereo plugin, does a little process the sum those 2 mono channels into stereo...
Click to expand...

Right....because you're using dual mono and forcing each stereo plug to do the summing.

Mix/sum the multi mono files to stereo FIRST....then apply stereo plugs....and then all the stereo plugs won't need to each do a sum of the mono channels.

You will still end up summing to stereo anyway...so whatever you think that does to the mono files....will still happen.
Sorry....but Mo Facta is right.
I'm sure there's some other folks trying your approach, but no, for the most part, the majority does it the other way.

Post up some audio samples....would love to hear what you are talking about.
 
So you export one stereo interleaved file and then two mono files and import them back in to a new project with no processing on the master bus(?), pan the mono files opposite one another and the manually A/B between them? Have you made sure to level match these two things before you do your test? Pan law will change the level of the panned tracks, but won't affect the stereo track. It must be compensated before you can make any valid comparisons. Then, of course, there's the fact that you "know" that there's a difference, and you know which one you're listening to at any given time. Not the most unbiased of testing methods. Have you tried a null test? They will need to be level matched exactly, of course, but the null test will tell if it's a real phenomenon or all in your head.

A stereo interleaved file should have exactly the same information as the two mono files, just wrapped up into one bundle instead of two. Unless PT does something really stupid in its mix bus.

If I really thought I needed to use an external editor to put the two files together, I'd use SoundForge.
 
BTW - I have a distrust for certain "stereo" processes also. A lot of software compressors will run in "stereo link" mode without giving you the option to turn it off. Back when I was mixing into hardware, I used to switch that switch regularly to see which I preferred, and frankly it was almost always the dual mono mode that worked better. Sometimes you just don't want the left side to duck out of the way of the right side. And don't even get me started on "stereo" reverbs...
 
Converting from multi mono to interleaved stereo is not summing because there is no change in the audio information, just the way it's stored. Mixing multi mono files or a stereo file to a single mono file would be summing.

How about some samples so we can hear what you're hearing? Wave files would be best. I'd also like to do a null test.
 
ashcat_lt said:
A lot of software compressors will run in "stereo link" mode without giving you the option to turn it off. Back when I was mixing into hardware, I used to switch that switch regularly to see which I preferred, and frankly it was almost always the dual mono mode that worked better. Sometimes you just don't want the left side to duck out of the way of the right side.
Click to expand...

The problem is that anything not hard panned will move left and right as the two compressor channels reduce gain differentially.
 
ashcat_lt said:
Oh I get that, but sometimes that "problem" ain't a problem. Best is to try both ways and choose by ear.
Click to expand...

I guess it just sounds weird to me when things move around in the stereo field in response to their collective dynamic envelope.

Don't forget the third option: don't compress stereo mixes/submixes. I don't even like compressing when mastering. Going back and compressing (or editing/automating) individual elements of the mix is my preference.
 
bouldersoundguy said:
Converting from multi mono to interleaved stereo is not summing because there is no change in the audio information, just the way it's stored. Mixing multi mono files or a stereo file to a single mono file would be summing.

How about some samples so we can hear what you're hearing? Wave files would be best. I'd also like to do a null test.
Click to expand...

After reading the first page I was going to say this but was beaten to the punch.

You're confused, OP. Bouncing to stereo interleaved sounds the exact same as bouncing to multiple mono. The only difference is bouncing to multi-mono means you have to .wav files that are half the size of the stereo interleaved file, because the stereo interleaved file is just conveniently making those two files into one. No summing or anything is done to the tracks. Left is still left and right is still right. There should be no change in whatever information is in the "middle" unless you changed your settings between bouncing from multi-mono and stereo interleave.
 
look guys,
I appreciate you're trying to help, but with all due respect i still think some of you misunderstand, think i'm imagining or just doing unfair test.
if i want to sum it up basically, it goes like this:
I master a project with multi-mono files. i bounce it out as stereo interleaved. then i import it back in the same project. when i A/B it sounds different. the stereo image changes, the middle gets a little more upfront. using all kinds of VOLUME meters for peak and RMS i can see that there is no difference in level.
what kind of other mechanism can cause these differences?
 
Maor said:
look guys,
I appreciate you're trying to help, but with all due respect i still think some of you misunderstand, think i'm imagining or just doing unfair test.
if i want to sum it up basically, it goes like this:
I master a project with multi-mono files. i bounce it out as stereo interleaved. then i import it back in the same project. when i A/B it sounds different. the stereo image changes, the middle gets a little more upfront. using all kinds of VOLUME meters for peak and RMS i can see that there is no difference in level.
what kind of other mechanism can cause these differences?
Click to expand...

Until we get to hear what you're hearing we have to go on the hard evidence we have, the "known fact" that they are just different ways to pack the same data. But I'm not at all convinced you're imagining things. That's why I'd like to hear even a sample of what you're working on. Would you be willing/able to bounce a short sample of interleaved and multi mono versions from your mastering session? Select a short section and bounce it both ways.

What I would do with the samples is bring them into my DAW, line them up, pan the multi mono tracks appropriately and invert the polarity on one version. It should cancel out 100% if there is no difference between them other than polarity.
 
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