Procedure for Maintaining Phase-Coherence - Multi-Mic (Drum Kit) - Elastic Audio

[skylar_battles]

Excellent question! So from some deep thought and research I believe when using a DI in addition to mics, there would be one more step in the procedure to maintain phase since the DI signal will arrive earlier than the mic'd sources as far as I understand. Also you don't need to remove the analysis markers from the track you will use to derive transients. You can just remove from all tracks except that one :)

In this video, it seems the recommendation is to slide back the amp signal so that it arrives in the same spot as the DI before editing the tracks as a group in order to maintain phase. Since, you have 3 mics and a DI the solution seems less clear to me. My best guess for this would be to move all of the mic tracks together (exclude DI) in order to line up the mic receiving the signal first with the DI. Then Un-suspend groups at same for the rest of the steps. Can anyone else comment on how to approach this? I'll do some testing soon...

[midnightrambler]

Happy to be corrected on this if I'm wrong, but I've *never* found a way of consistently keeping phase coherency between groups of individual tracks for multi-mic'd bass/guitar/etc using Elastic audio, and I've tried lots of different methods over the years (including the one posted by the OP).

The only way I've managed to successfully get away with this is by moving all of the individual tracks onto *one* single multichannel track of the appropriate width, consolidating those files to end up with one multi-channel file, and then performing elastic audio edits on that single file; you can then either send the outs on that track onto mono aux tracks (so you effectively still have individual tracks to balance etc), or consolidate the edits and then "Split into Mono" to get the individual tracks back again. I prefer the former as it means that you can carry on editing without having to commit those changes until the very last minute.

Oh, and unless there's been some sort of bug fix I would stay the hell away from Elastique if I were you. It's fine while it's running "live", but as soon as you commit all sorts of weird stuff occurs (tracks go out of time, lumps in audio...)

[weezul]

I swear in pt 7 to 10 this method used to be fine. Something down the line changed the accuracy of EA. elastique especially is not fit for purpose. Consolidation ruins it. The early days of EA i felt were the best, digi even had a tutorial about multitrack drums showing the phase coherence at the end. Anyone remember that? Bald guy in lots of videos

[midnightrambler]

Originally Posted by weezul

I swear in pt 7 to 10 this method used to be fine. Something down the line changed the accuracy of EA. elastique especially is not fit for purpose. Consolidation ruins it. The early days of EA i felt were the best, digi even had a tutorial about multitrack drums showing the phase coherence at the end. Anyone remember that? Bald guy in lots of videos

Yes AlexLakis (Hi Alex!) reported on this years and years ago...

https://duc.avid.com/showthread.php?t=273219

[audiogamble]

Regarding the comments on elastique and consolidation, that big is fixed now. The algorithm itself works fine even after committing. I just think it doesn’t acknowledges phase within edit groups, which seems to simply be how EA works regardless of algorithm.

Regarding my specific issue with the guitar DI, I do understand that the DI’s timing will be earlier than the amp but that isn’t the issue. At worst, the only problem would be that the amp signals feel a bit late which is something I can manage. The problem is that any amount of quantizing with EA crates noticeable comb filtering across the recorded mic signals.

What’s confusing me though is that in the manual, avid states:

“élastique Pro offers stable timing and inter-channel phase coherence”

Can anyone from avid comment on the phase coherence claimed here? Are there specific conditions that will keep tracks in phase with each other?


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[albee1952]

Let your ears be your guide. Phase between tracks on a fully mic'd drum kit is a constantly moving target with any process that stretches audio. This is why Beat Detective is often the better option for drums

[skylar_battles]

Thanks for your responses everyone, really been trying to figure the best approach for this even though I just use Beat Detective honestly. If there was a way that we could trust, that would be pretty cool!

midnightrambler: I'm confused how after using the stereo bounce of the drums to time stretch that you can make use of the of the original tracks for any purpose? I'd think after time stretching the drum group on a stereo track you would lose the ability to mix the individual elements because the originals wouldn't be timed?

weezul: Interesting that in the past it's worked better and the procedure was documented.

audiogamble: FWIW I don't think any of the algorithms can or do maintain phase inherently, so I'm confused by zPlane's claim. Maybe inter-chanel coherence refers to multichannel files? I still think even by time-stretching you'd have to manually align the DI to the mics b y moving it later and then use the steps at the beginning. I'd hope it would work buy I haven't tested yet!

[midnightrambler]

Originally Posted by skylar_battles

midnightrambler: I'm confused how after using the stereo bounce of the drums to time stretch that you can make use of the of the original tracks for any purpose? I'd think after time stretching the drum group on a stereo track you would lose the ability to mix the individual elements because the originals wouldn't be timed?

A) I wouldn’t use this method on multi mic’d drums. Sorry should have made that clearer. Was talking specifically about the example given of 1 musical instrument recorded using multi-mics. It’s basically a hack in order to maintain phase coherency between the various mics.

B) There’s no reduction or stereo bouncing involved. For e.g. a guitar with 3 mics, move all 3 files onto a single track that is “3 wide” (i.e. LCR). Then consolidate. Then all stretching etc will be on that one, multi-channel file.