SMTPE vs Varispeed for Tempo Control

[Maestro777]

So I intimately know the use of SMPTE from my days of recording material to tape (both video and audio) but I'm just a bit unclear as to the benefit of SMPTE as some are using it within Logic to lock in the tempo of their work to simply be able to change the speed. Would Varispeed accomplish the same task in that type of scenario? And with a much minimal amount of work? Not saying a couple of seconds difference is a huge time saver but....?

I can immediately realize the usefulness of SMPTE if I'm locking my material to video or when in need of any type of synchronous operations to other material and/or devices. But what real benefit does it serve for sole intent of locking the tempo of all the tracks to speed or slow down when Varispeed can do that equally as well???

 

Edited January 28 by Maestro777
Clarified Topic

[David Nahmani]

They're really different workflows for different uses. You can lock SMPTE for individual regions, Varispeed is global for the entire song. 

You probably already know this but just to clarify, SMPTE is just a time unit based on real time (hours minutes...), vs your Bar/beat clock which is a time unit based on the tempo of the piece. 

By defaults, regions are locked to the Bar/beat clock, so if you change the tempo, the regions stay on the same bar number, and therefore are no longer at the same SMPTE position. 

If you lock a region to SMPTE then it's the opposite behavior: when you change the tempo the regions stay on the same SMPTE position, and therefore are no longer at the same bar/beat position. 

MIDI Bar/beat locked regions play at the new tempo. Audio Bar/beat locked regions play at their original tempo unless you've enabled Flex for the track. 

SMPTE locked regions (audio or MIDI) always play at the same speed even after you change the tempo. 

Varispeed allows you to change the tempo (and optionally pitch) of the entire project, globally, all the tracks follow, all the regions are bar/beat locked and play at the new tempo. Much playing a tape faster or slower. 

Hope that makes sense? 

Let's say I'm writing a soundtrack for a movie, using MIDI to trigger sample libraries, and there's an explosion sound just when the car crashes into the wall. I want to slow down the tempo of the music. I lock the explosion sound to SMPTE (so it stays locked in time exactly when the car hits the wall) and change the tempo, which affects all the other regions that aren't locked to SMPTE. 

[Maestro777]

Ok, got it. So you can't really use them interchangeably as the 2 serve very different scenarios and purposes.  The explanation of how the regions are affected by each really brings clarity. Thanks David

[David Nahmani]

8 minutes ago, Maestro777 said:

So you can't really use them interchangeably as the 2 serve very different scenarios and purposes. 

Yes, that's it. You're welcome! 🙂