Adjust Logic Tempo to match imported audio file?

Question

Adjust Logic Tempo to match imported audio file?

Before switching to Logic, I used GarageBand to record covers of songs. I'd import an MP3 of the original song and then perform and record each instrument in separate tracks to replicate the song. Ultimately, I'd mute the original recording and have my own masterpiece replica.

Now that I'm in Logic, I want to quantize (and do a lot of other things to) my imported recordings but so much depends on having tempo set correctly. Since my GarageBand recordings had a commercial audio file as my "click track", I didn't need any other tempo guide so the GarageBand files were defaulted to 120bpm.

I've tried unchecking "Follow Tempo" for each track, creating an 8 bar section of my recorded audio, setting the locators to spam 8 bars and using the "Adjust Tempo Using Region Length & Locators" function. This does well for the 8 bar region of audio but messed everything else up.

Can I just set my recordings to begin on bar 1, beat 1 and then manually fiddle with the global tempo controls until I dial in the perfect tempo? Because it's a commercial track, I'm pretty sure it's already locked to a fixed tempo so I don't think Beat Mapping is necessary.

Any ideas of how to accurately configure my tempo after doing all these recordings?

THANKS!
-Aaron

Mac Pro 2x2.66, MacBook Pro 13" 2.53, Mac OS X (10.6.1)

Posted on Oct 19, 2009 5:28 PM

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Answer 1

bill borez

Level 4

1,210 points

Oct 19, 2009 5:52 PM in response to aaroneousmonk

You can do better than that, you can select the Audio, then go to the audio menu and select detect tempo and it'll tell you what tempo they are.

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Answer 2

Oct 19, 2009 8:43 PM in response to bill borez

Thanks for the great lead, Bill. I wasn't aware of that option.

So, now that I ran "Detect Tempo" and know the 154.2587 result (which I actually think is double-time), what do I do? I tried manually changing the tempo in the transport area but that screws up the start times of all staggered tracks and the beat markers still don't seem to correspond to the song beat.

Do I need to manually re-adjust the start points of all the tracks?

I first unchecked "Follow Tempo" for each track that gave me that option (half the audio tracks did not give me that option--do you know why?).

Lastly, when I go to the Tempo Global Track, there are drop-downs for Resolution, Alternative & Quantization... what is Alternative?

Thanks so much. I watched all the Logic 8 and 9 videos at Lynda.com but that just scratched the surface--steep learning curve.

Thanks so much.
-Aaron

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Answer 3

Oct 27, 2009 2:47 PM in response to aaroneousmonk

Any other ideas on how I can get the tempo changed? Seems like it should be an easy task for an experienced Logic user.

Thanks,
Aaron

Message was edited by: aaroneousmonk

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Answer 4

Jan 19, 2010 1:22 PM in response to aaroneousmonk

Before you change the tempo, select all your tracks and in the Arrange window go to Region>Lock SMPTE Position. That way they will move with the SMPTE markers when you change the tempo.
You then need to unlock them to move them again.

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Answer 5

Jan 19, 2010 2:28 PM in response to aaroneousmonk

Aaron,

I do this daily as I do a lot of work for karoke companies.

You need to get familiar with Beat Mapping in Logic. There are only a small number of songs that are going to come in at one steady tempo. Dance things, that kind of stuff. Most will have the tempo moving around throughout.

1 I start with a BPM calculator to get me close so I can set something initially, just to get a ballpark for the count in (I place the original audio at bar two after trimming it).

2 After using DETECT on the waveform of the file you want to match, and after choosing BEAT MAPPING as a Global Track to be displayed, you can now see where the transients are in the real piece, verses the tempo you set. You can go bar by bar through the whole song and just drag the lines down from YOUR tempo to match the downbeats of the song. You can get real real tight this way.

3 If getting it ABSOLUTELY tight is not that necessary and you just want to get close, you can create a midi track with some percussive sound on it and tap along with the real song. When you're done you can fix any errors in your tapping, then highlight the whole region of taps you did and choose "BEATS FROM REGION," then QUARTER NOTES in the next dialog, and you're done. Logic changes the tempo track to match what you've clicked. It's fine for quick and dirty.

TH

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