Logic: Flex Time Tutorial by Lostnthesound

lostnthesound

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I had posted a mini tutorial inside of another post, but I thought it may benefit the lot if I created a more detailed thread specifically about this topic.

As many of us know, applying the quick and easy time stretching in Logic (option + drag) can create mixed results, especially when it comes to vocals or attempting to time stretch a region well beyond it's original BPM. When switching the stretching algorithm to complex (or percussion for drums) isn't doing the trick, it's time for Flex Time to step in. Big thanks to my Stepchild production partner-in-crime msmith222 who first put me on to the potential of Flex Time.

The following are some tips and tricks with regards to the omnipotent tool that is Flex Time.

Things to Keep in Mind
  • Flex Time works best when working with dry audio regions. If a sample is extremely wet with reverb, delay, etc. you may experience some unwanted audio artifacts. Basically, the cleaner the file, the better.
  • Flex Time modes (poly, mono, speed, etc.) all yield different sounding results. We'll dive into this a bit deeper later, but don't be afraid to experiment. I typically stick to mono, slice & tempo.
  • For best results, transient markers should be located at the quietest parts of the wave form, this will yield the cleanest sounding results.
  • Once you have Flex Mode active on a track/region, you can freely switch between Flex Time's different settings (poly, mono, speed, etc.) to hear the different results and decide which one works best for you.


Flex Time: Vocals.
The other day whilst browsing through my samples I came across a lovely acapella from the High Rankin Female Vocals audio sample pack. While the vocals are tits, they're all set to 140 BPM. In order to make the vocals match my desired tempo 175BPM without putting in too much effort, this is what I did.
  1. Set the current project to 140BPM to match the tempo of the vocal I wish to edit.
  2. Double click the audio region to open up the editor window.
  3. Within the editor window, select File>Detect Transients. Logic will now quickly setup transient markers throughout the audio region.
  4. While still in the editor window, locate the +/- buttons. These buttons will either reduce/increase the number of transient markers. As a rule of thumb, the less markers, the better the result.
  5. Exit out of the audio editor window and select the track/region of the sample. Now activate Flex Time by pressing the "Flex" button.
  6. Select the "mono" Flex time option (Note: using the "Slice" option will give the vocals a "chopped" Danny Byrd-esque feel. Using "Tempo" option will alter the pitch of the vocal which may be the effect you're after).
  7. Now, change the project tempo back to 175. Voila!! The transient markers via flex time have "wrapped" to the new tempo.
  8. Listen to the track as a whole. If some of the vocals sound slightly off we can quickly fix this. Locate the flex time transient markers that are at the points of the vocal that are sounding off. Now simply click and drag the markers so that they match up with the beat.
  9. Once you're satisfied, you can either bounce your Flex Time edited region in place or you can convert it to an Apple Loop, which will embed transient markers into the file and allow you to use the file later in another project without any further flex editing needed. And if you feel the need to adjust the Apple Loop markers at a later time, simply open the file in the Apple Loops editor.

Advanced Flex Time: Drums.
This is a bit more advanced, but some experimenting will yield some great results.
1. Import an audio file of nice break with well defined hits.
2. Double click the region to open the editor.
3. Select file>detect transients.
4. Once again, use the +/- buttons to add/remove transient markers. This is especially important since we're dealing with drums. We want to make sure our transient markers show up only at the strong hits of the region.
5. Close the audio editor and select the track/region of your break audio file.
6. Click the Flex Time button and change the Flex setting to "Mono."
7. Now comes the fun part that requires a bit of trial and error. Select a transient marker within the break the is placed near a hi hat or percussion hit. Don't move it yet, just make sure it's activated.
8. Now find a nearby transient marker of another hit, activate it but don't move it.
9. Return to the transient marker we activated in step 7, and move it towards the marker we activated in step 8. Eventually, the two markers will merge.
10. The end result should be a break that has been slightly shuffled due to the time change. You can also use the "Slice" Flex mode during this process for shits and grins.
11. If the result sounds bad, try again with different transient markers. Don't get discouraged.

To conclude flexing vocals (or any audio region for that matter) will take a little bit of time getting use to, especially when it comes to having to reposition the transient markers that may be slightly off the beat. Exercise a bit of patience and trial & error and Flex Time will be your new best friend...or mistress. Don't be afraid to experiment with different flex settings or marker placement to discover new creative sonic possibilities.

One day when I'm feeling motivated, I'll drop in some audio examples and some visuals. I apologize upfront for any typos and will edit them as I notice them.

Cheers.

FAQ
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  1. "Lost, my vocal sounds like shit and contains weird "click" noises. What the hell?"
    Well my good friend, check your transient markers. Are there too many or too close together? Try deleting markers that are too close or extra markers (right click > delete marker). Also, are your transient markers located at the louder parts of the waveform or in the middle of part of a vocal line? Delete that shit.
    <br>
  2. Lost, I notice the colors change as I'm shifting around the markers. What do they mean?
    Orange means the area has be increased (will play slower). Green means the area has been condensed (will play faster). I find when adjusting audio regions to DnB, Green/Light Green is the best color to aim for. While it's not essentially that all the areas are the same color, nine times out of ten it will yield the best results.
    <br>
  3. Lost, my entire audio region is green when in flex time and sounds great. However, the tail of the file is orange, slow and sounds like shit.
    Simply insert a marker at the end of the file and condense that area. Or, you can hold option and squeeze the file. HOWEVER, note the position of your cursor when you hold option and begin stretching–as with many things in Logic, right clicking or holding option yields different results when the cursor/pointer is aimed at different areas of the region (bottom, middle, top).
    <br>
  4. I turned off Flex Time, now my files aren't playing with the tempo and I lost all my time changes. HELP!
    Activate Flex Time again via the Flex button, they're still there. I like to bounce/bounce in place my Flexed files (or convert to Apple Loops) after I've Flex edited them. That way I can start from a clean slate and start to further process the audio (EQ, filter, etc.)...not too mention it will keep me from going back and further editing the Flex markers to make them "better," when in reality I'm wasting time.
    <br>
  5. I dropped in a wave file. I then disabled the "Follow Tempo" in the inspector panel. However, when I activate Flex Time, the Wave files compress on their own and sound like shit.
    This is an unfortunate side effect of a wave file that has either been Acidised or improperly Acidised. Some of you may have noticed when placing certain wave files/loops that they sound like shit, even though your project tempo/key is identical to the file you're placing. This is an annoyance that occurs with Acidised wave files in Logic for whatever reason. The fastest way around this bug is to simply bounce in place the Acidised wave file (ensuring you have disabled Follow Tempo and Flex Time). This will create a new audio file without any of the Acidised metadata bullshit to cramp your production time.
    <br>
  6. In the inspector panel with a region selected and Flex Time active, I noticed a Quantize option...
    Yes, you can set a Quantize value and the markers will snap to the value. This works better on drums/percussion IMO. But do whatever works/sounds best for you.
 
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nice dude, will come in handy, never really used it in logic but within 2 minutes ive got some good sounds going. thank you very much sir, the internet needs more people like you
 
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