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Logic Pro record slowly then speed up

edurbrow

edurbrow

Logician
What is the best/safest way to record, say, a guitar solo, slowyly then speed it up? Varispeed? I mean, in order for the audio region to come out as clean as possible.
 
Solution
AlexDingley
Here's my thoughts, as someone who doesn't play a lot of guitar solos, but who's done a ton of time-stretching/modifying.
  • You couldjust varispeed down to as low as 50% and record. But I've not done it, so I can't speak to the quality of the re-sped-up results.
    • Your original post was from October, so I have to imagine you've been experimenting since then. Have you tried this / how'd it go?
    • This method is likely the fewest steps... but if it doesn't sound great, I would do another experiment with this process at a higher sample rate (if possible). My experience is that any time-varying work tends to benefit from "more samples per second" because there's more info to play with / interpolate from.
  • But my...
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Hey there — so, I'm guessing nobody answered because the solution probably doesn't align with your question. Here's the big question(s):
  1. How different is the speed at which you'd like to play vs. the speed you want the solo to playback? (can you give the answer in beats-per-minute?
  2. Is there already other material that you'd be recording on top of, or are planning to play this freeform?
  3. What audio sample-rate are you recording at? 44.1KHz / 48 / 96 / etc?

Depending on those details, the answer will vary quite a bit.
 
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  1. How different is the speed at which you'd like to play vs. the speed you want the solo to playback? (can you give the answer in beats-per-minute?
  2. Is there already other material that you'd be recording on top of, or are planning to play this freeform?
  3. What audio sample-rate are you recording at? 44.1KHz / 48 / 96 / etc?

1. Well, I'd say half or 3/4 speed, maybe. I'm interested in this in different circumstances, so sometimes 90% may be enough.
2. Yes, definitely. And I don't want all the other regions to get messed up.
3. Why would the sample rate mater? I try to do everything in 48kHz, but many files are already in 44.1kHz.

So these various answers depending on details are what I am interested in.
Thank you in advance.
 
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Here's my thoughts, as someone who doesn't play a lot of guitar solos, but who's done a ton of time-stretching/modifying.
  • You couldjust varispeed down to as low as 50% and record. But I've not done it, so I can't speak to the quality of the re-sped-up results.
    • Your original post was from October, so I have to imagine you've been experimenting since then. Have you tried this / how'd it go?
    • This method is likely the fewest steps... but if it doesn't sound great, I would do another experiment with this process at a higher sample rate (if possible). My experience is that any time-varying work tends to benefit from "more samples per second" because there's more info to play with / interpolate from.
  • But my money would be on doing the process "backwards": (make a slow copy of the mix and play to that / then speed-up your played performance and re-insert it into the song)
    • Take the existing passage of music and print/bounce a rough mix of it so that you have a stereo track of the passage right there in your session.
    • Make cuts in that mix-down stereo track so that you have the passage you want. (it's gonna be important for timing reasons to make sure you do some on-the-downbeat cuts, so that when you do the later time-stuff we're getting easily-alignable regions)
    • Drag that passage waaaaaaaay later after the end-of project so that it's no longer overlapping with the original material at all.
    • Time-stretch that passage to be 125% / 150% / 200% longer — you can do this by holding the option-key while you drag the end of the audio region. You can do this other ways, but option-dragging is nearly instantaneous & you don't have to leave the main arrange window to do it. (and if you have the default 'smart' snapping enabled, you should easily be able to take something that's 16bars and make it 24 or 32 bars because your region will still snap-to those measures as you drag out the region-end)
      • 16-bars dragged out to 24-bars is gonna allow you to play 25% slower
      • 16-bars dragged out to 32-bars is gonna allow you to play 50% slower
      • if your half-speed playback sounds kinda wonky... fear not. it won't be part of your eventual mix. You're gonna discard it when you're done.
    • I did a quick google-search on this time-stretch method and one of Mikael Baggström's youtube videos came up (he has a ton of solid Logic tutorial content) I made that link jump immediately to the section where his mouse transforms as he hovers over the region-edge. That's the visual cue you want to see when you're successfully time-stretch-dragging.
    • Play the guitar to that slowed-down section and get it just right.
    • Make sure to cut slices so that the solo region is exactly the length of your stretched region (exactly 24 or 32 or X bars long)
    • Stretch-drag the guitar performance back to the original number of bars.
    • Drag that guitar performance back to the original time in the original passage of the session. — if any small nudges are needed to get the downbeat of the solo right, you can just command drag it so that smart snapping is ignored. — Alternately; you might even open the sample editor of the region and use the anchor point line to ensure that the solo snaps to whatever bar you want it to.
I'd be curious if this works for you.
 
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Solution
Awesome! — if it turns out great, then post a link. Frankly, I've been in a creative rut for a while, and sharing my 16+yrs of Logic experience to help other solve problems is partially my own exercise in re-igniting the creative fire. So you're welcome + thanks for letting my try to help.
 
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Well Alex, it has been more than a year, since this thread was started, but I finally tried out your technique tonight. It worked a charm. I had an impossible bass part that went at 120bpm. I moved the drum and midi bass of the chorus to an area after the finish of the piece and lowered the tempo to 80. After a few tries, I got something reasonable. I engaged Flex. I quantized the beat transients then trimmed the part to the bar lines. I then simply moved the tempo back up to 120 and it sounds great. Luckily this piece doesn't have any changes in tempo. Also it is only 4 bars which repeats four times. Now I'll record the rest of the bass part at normal speed. I already have a video finished. I need to redo the guitar part. Hopefully, it won't be too long before I can post a link.
Thank you again for a very detailed suggestion.
 
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Woah! I'd forgotten about this — You're welcome, and I'm so glad you're happy with the results. I'm a firm believer that there's always a way if you're willing to think creatively about the approach.

Definitely post the results here when you're ready.
 
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And it is another year later and guess what, I finally posted the video. You can hear my virtuoso bass playing in the chorus.
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Thanks again.
 
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