Music tempo adjustment software for Mac?

July 31, 2012 8:41 PM

Can you recommend free/very cheap software for a Mac that allows me to slow down recorded music (mp3s) on the fly?

I teach folk dance to recorded music, and often the tracks are too fast for our dancers to keep up with. When I can anticipate this, I use Audacity to slow down the tempo without altering pitch, and save the file as a new track -- but I don't always anticipate correctly, and even when I do, I'm not always right about how slow to make it. One of my fellow teachers, who is on a PC, has software that can slow any track down -- she puts her playlist for the evening into this application, and it has a slider to adjust tempo. I'm looking for something similar, $10 or less, for Macs (this is a volunteer gig that I already spend too much money on!).

I'm not a professional at this and apparently suck at Googling without the right vocabulary, so I apologize for the lack of appropriate vocabulary and if I missed an obvious solution.

posted by obliquicity to media & arts (19 answers total)

Would this help? http://www.ronimusic.com/amsldox.htm
posted by blaneyphoto at 8:47 PM on July 31, 2012

Do you have GarageBand on your Mac? If yes, you can just drag the MP3 into a new project - a Voice project will work fine for this.

Now, just follow the instructions from here. Copied and pasted and slightly modified below:

1. Drag your audio file (MP3, M4A, ...) in GarageBand. It's shown as an orange track.
2. Press Ctrl+Alt+G
3. Click the audio track. It is now blue/purple.
4. Check "Follow Tempo & Pitch" (this is in the wave editor section, which you get by clicking the scissors symbol next to the eye)

Now, click the little icon to the left of the blue time display at the bottom of the screen and switch it to "Project"

5. Now change the tempo while the song is playing by clicking the number under "Tempo" and pulling the slider down to your desired speed.
posted by plasticbugs at 9:10 PM on July 31, 2012 [3 favorites]

Quicktime Player 7 does this, too - but in a much simpler way that offers slightly less control, allowing 1/2 speed at its slowest.

1. Open your MP3 in Quicktime Player 7 (not the more recent Quicktime Player).
2. Window > Show A/V Controls
3. Play song
4. Drag playback speed slider (doesn't affect pitch, just speed).
posted by plasticbugs at 9:15 PM on July 31, 2012 [1 favorite]

VLC does this through the 'Playback' drop-down menu as well as on the GUI. If you click the 1.0x in the lower-right corner it'll display a rheostat to adjust the playback rate.
posted by carsonb at 9:20 PM on July 31, 2012 [2 favorites]

The Amazing Slow Downer seems really overpriced, to me, at $50. Transcribe! is $10 less and works harder to justify its price. I would buy it, except that I have Anytune Pro HQ for the iPad, which was $15 and works just fine.

In your shoes, I'd probably go for iRehearse. It's $15, which is above your price point, but way easier to use on the fly than Audacity.

On preview, I had no idea Quicktime Player would let you do that. Neat.
posted by hades at 9:40 PM on July 31, 2012

iRehearse does look like the best fit so far, hades -- especially because it can handle a whole playlist!

The Garageband instructions are even more complicated than doing it in Audacity (technically possible on the fly by doing roughly the same thing) -- I'm trying to avoid multiple steps per track because by the time we discover the tune is too fast, we've often already spent 10 minutes learning the dance and are in the middle of dancing it -- so the dancers get frustrated if I then stop the dance to fuss with technology for more than 7 seconds.

I am checking out Quicktime 7 -- it does sound like a great quick-fix solution, so thank you, plasticbugs. I usually slow things down a maximum of 25% -- otherwise it doesn't feel like we're dancing anymore!!

The Amazing Slow Downer has come up when I've searched, but I was a little blown away by the cost -- I cannot emphasize enough that I don't want to spend more than $10 (okay, maybe $15 since iRehearse does look like a nice solution) on a gig I'm already volunteering for (and driving 140 miles r/t to be at). It's fun, but it's enough of a money pit already :)
posted by obliquicity at 10:03 PM on July 31, 2012

Seconding VLC. Apart from having the specific slowdown feature you're after, it's an absolute workhorse of a media player. I very rarely use anything else these days, on any platform.
posted by flabdablet at 10:17 PM on July 31, 2012 [1 favorite]

One of my fellow teachers, who is on a PC, has software that can slow any track down -- she puts her playlist for the evening into this application, and it has a slider to adjust tempo.

This could well be VLC.
posted by flabdablet at 10:19 PM on July 31, 2012 [1 favorite]

Correct me if I'm wrong, but I believe VLC and the Amazing Slow Downer both affect the pitch of the music, which would render the effect useless to the OP.
posted by plasticbugs at 10:45 PM on July 31, 2012

Consider yourself corrected.
posted by flabdablet at 11:11 PM on July 31, 2012 [2 favorites]

VLC is definitely what you want. It has playlists. It slows down without slowing the pitch. It's free. It has both keyboard commands for slowing and an interface. Top-notch.
posted by Mo Nickels at 8:37 AM on August 1, 2012

I asked a similar question a while back. My dance group now uses a pc, WinAmp, and a plug-in.
posted by theora55 at 8:47 AM on August 1, 2012

After taking a long hard look, VLC is almost definitely not going to work for this purpose in OS X. The Windows version allows what you're looking for, but not the Mac version. Anyone in this thread who's touting VLC as the answer is probably not using a Mac.

If they are, I'd love to hear how they're able to slow down a track in the way that's been described.
posted by plasticbugs at 10:10 AM on August 1, 2012

Okay, I'm back with good news. VLC for Mac can do what you want but you have to follow these steps to remap the hotkeys for speed up and slow down to 'Faster (fine)' and 'Slower (fine)'. It should only take a minute to do.

I'd use Command+ and Command- to make it easy.

Good luck!
posted by plasticbugs at 10:47 AM on August 1, 2012 [1 favorite]

I just tested VLC 2.02 on a Mac (Lion) go up to the Playback menu and there is a speed slider right in the dropdown, however I don't think you can save/export the slowed down version.
posted by Lanark at 10:51 AM on August 1, 2012

Is this documentation out of date, then?
posted by flabdablet at 10:52 AM on August 1, 2012

There's a Mac version of Paulstretch here. It will do extreme slowdowns without pitch changes but you set it to be a lot less extreme. (It's what was used to make the ambient version of Beiber's "U Smile" that was Internet-famous a couple of years back.)

There's also a command-line version in Python here if you're into that sort of thing.
posted by suetanvil at 1:59 PM on August 1, 2012

I appreciate all the follow-up conversation about VLC for other researchers' sake, but to be honest it seems like overkill for my needs in most ways, and underwhelming in others (keystroke commands or the slider hidden inside a menu). And personally I found the website and the wiki mindbogglingly user-unfriendly (go ahead and joke about how that's why I use a Mac).

theora55, if my group was providing the equipment then this wouldn't be a question -- but I have to use my own, and I'm not going to buy a PC just for this!
posted by obliquicity at 3:09 PM on August 1, 2012

@flabdablet Looks like I need to update my moldy version of VLC. Thanks for the follow up! :)
posted by plasticbugs at 5:19 PM on August 1, 2012