unwanted pitch change/transpose when auditioning in logic, but "ok" when Share-to-iTunes

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unwanted pitch change/transpose when auditioning in logic, but "ok" when Share-to-iTunes

Logic Pro 10.4.8

Mojave 10.14.16

I have a project where "suddenly" (I can't determine what changed), some tracks are playing back transposed (by a half step and in one case 4-steps), but other tracks are playing normally. I've checked the global Project Tuning - it's set to 0. I've checked both Track and Region "transpose" settings - none are set. All tracks are software instruments - all instruments are Alchemy - and none of them have odd "tuning".

One possible clue: on the latest project, the tracks playback transposed when I audition them with the Play button in Logic. But if I then Share->to iTunes, the resulting M4A file is NOT TRANSPOSED.

I hope that's a useful clue to someone - it makes no sense to me!

This has now happened on two different projects and I'm at my wits end. What should I be looking for?

MacBook Pro 13″, macOS 10.14

Posted on Aug 12, 2020 5:32 PM

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Answer 1

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Chine Nual Author

Level 1

10 points

Aug 13, 2020 1:42 PM in response to Iaamusic

There was no modulation automation at all. Very odd. MIDI event listing was clean.

I have "solved" the problem - but without a real explanation. Remembering a problem I had some months back when a control surface started spewing noising data for one of its CC knobs, I started unplugging stuff from my USB hub. One by one - nothing made any change. Then I unplugged the last device (a USB serial cable) and -- to my amazement - Logic started behaving normally. What's even better is that when I plug everything back in, it's still working normally.

So "something" (the serial cable?) was probably causing some noise on USB that Logic was misinterpreting and randomly detuning my tracks.

When this first started happening, I suspected the noisy control surface, so I tried unplugging it (and it didn't help). Didn't think until now to unplug _other_ USB devices. Let that be a lesson!

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Answer 2

Chine Nual Author

Level 1

10 points

Aug 13, 2020 10:54 AM in response to Chine Nual

I'm still banging my head on this. The MIDI has no pitch automation, the instruments are not detuned, the track and regions have no transposition. Here I've simplified things to play the same MIDI notes in two tracks with two different instruments - one a sampled piano, the other an electric piano. The should sound in "unison" - but clearly they aren't!

https://youtu.be/WCT5aSBfWCM

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Answer 3

Chine Nual Author

Level 1

10 points

Aug 13, 2020 12:27 PM in response to Chine Nual

I've tried restoring Logic Pro X.app from a January backup -- makes no difference. Compared all the contents of the backed up app and the current one - no changed files.

I've tried restoring ~/Library/preferences/com.apple.logic.pro.cs and com.apple.logic10.plist -- does not make a difference.

My machine is cursed! Ideas for other files that I should try to restore from backup?

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Answer 4

Iaamusic

Level 4

1,348 points

Aug 13, 2020 1:21 PM in response to Chine Nual

Do you have any errant modulation automation. Sometimes wonky controllers or inadvertent controller assignments or even shortcut keys (like the play button) can create these kinds of issues.

worth checking your midi events on the affected track whilst it’s playing to see if there is anything odd there.

you could double check the sample rate in the sampler too - some instruments have different sample rates which can be an issue. Rare but if everything above is ok...

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Answer 5

Iaamusic

Level 4

1,348 points

Aug 13, 2020 1:51 PM in response to Chine Nual

Yes, it’s always worth trying to get to a “clean” system. Glad you sorted it!

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unwanted pitch change/transpose when auditioning in logic, but "ok" when Share-to-iTunes

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