Random, unintentional, subtle changes in pitch

Hi! I’ve had some problems with Audacity over the past several months, running 2.0.5 (from the zip) on OS 10.9.3; many/most third-party plug-ins crash, or don’t work at all (including the Apple AU’s). But one particularly troublesome issue is a gradual change in pitch during playback, out of nowhere. It is just the, most… weirdest? Sure, the most weirdest.
It sounds like running a tape reel or turntable, and pressing very gently to gradually slow it down, maybe just holding it there, or very slowly releasing, progressively resolving the track’s apparent pitch. The net change is minimal, in either direction.
I equate it to slowing down an analog source, but I honestly can’t tell if it’s also affecting tempo; the one automatic thought I have any time this happens is "help me my ears are slowing down :open_mouth: " so I assume I’m detecting a full rate change, tempo and pitch.
This is nothing intentional or effect-related, and it doesn’t repeat from one play to the next, so it’s both insane and irregular.

I’m certainly not as tech- or sound-savvy as I hope I am, but I wouldn’t expect this to be happening in digital audio, with 16GB of RAM and a decent processor. Can anyone confirm that Audacity might play out this way, and- if so- have suggestions for more faithful playback? Thanks!

What’s the computer? Intel MacBook Pro?

Apple (upper left) > About This Computer. Command-4 and draw a box around that little INFO panel. Post the screen capture here.

Does it always slow down?

It’s concerning that third party plugins cause Audacity crashes, but nobody is going to fall over in a faint. It’s much more concerning that the Apple AU filters don’t work.

There was a very recent enormous system upgrade to Mac OS-X. Over a gig of download. I went shopping and coffee during the install. Did you apply it?


Did you actually install Audacity? Double click the ZIP to get the DMG file. Open the DMG and drag the Audacity folder to the /Applications folder? If you’re trying to run Audacity from inside the DMG, it can be profoundly unstable.


Screen Shot 2014-07-04 at 4.55.14 PM.png
I don’t have enough control over this bad boy to apply updates myself, so I’m not certain of its status vz current patches.
While I am not running Audacity from within a DMG, I am running it from within my local user Applications folder, not the system Apps; ditto the effects, which are either in the Audacity folder or my User : Library : Audio : etc. directory. That’s the reason I haven’t ever really hit the forum about plug-in problems, I can’t be certain about any particular contributing factor, and I couldn’t possibly comply with a good set of troubleshooting instructions. (I probably shouldn’t have brought it up in the first place, sorry about that)

Regarding this pitchshifter thing, which was my real reason for posting, I’m now actually noticing it with iTunes as well, on and off.
I would guess that the changes are up to about a quarter semitone. I may hear one song dip, then come back; if I play that song again, it may be fine, or it may be affected at a different time.

But it seems impossible, right? For a computer to play music like almost imperceptibly-warped vinyl, all by itself… it’s like my laptop became self-aware, and just wants to screw with me.

I was kind of banking on someone shouting “yes me too” about this, otherwise it seems like it would be very difficult to pursue much further. And, of course, it’s not actually an Audacity problem anymore, anyway.
I’m going to shift gears, I think, and consider… I don’t know. Maybe seeing a neurologist. :confused:

I was kind of banking on someone shouting “yes me too” about this

So then you’d both be lost.

But seriously, Most people Blitz Post, where they post a question, get the answer and we never see them again. The business of “users helping each other” is a fantasy from when programmers used to help each other like that in 1968.

So it’s only if one of the forum elves happens to have your exact hardware and software configuration would that be helpful.

It’s troubling that you have no system access to your computer. Can you go into why that is? No system access means you can’t do a drive test or diagnostics and it also means you have probably never done an Apple Update.

And you’re correct, “finger on the record” slowing down of playback audio is most unusual and I would be doing System Administrator things to see if I could find out what was wrong.

I suspect the first time an administrator logs in, they will get several very urgent messages about machine health.


As far as Audacity is concerned you should be able to run Audacity from anywhere on the hard drive, but don’t drag Audacity.app out of its “Audacity” folder.

It’s possible Apple’s AU effects are confused by your putting Audacity in the user Applications folder. What do you mean exactly by the Apple AU’s don’t work at all?

Can you post some crash reports due to third-party plug-ins? Open Finder, then choose Go > Go to Folder and type:



What audio device are you using for playback? USB or Firewire interface? If so please give make and model number.


Thank you both for taking all the time to think this through!
Continuing backwards: I’m running the Core Audio bus to headphones or a bluetooth speaker.
Screen Shot 2014-07-05 at 6.50.49 AM.png
I’m not working with a DAW right now, so no associated latencies, etc… this is all next level wtf to me.

The issue with Apple’s AU’s is also quite bizarre. Some of them do seem semi-functional, I’m discovering that it’s the preview that kills the functionality: if I don’t preview, I may be able to make some adjustments and hit Okay, and it may work for some of the units; but once I try to preview, the settings can no longer be changed- the sliders can move, but the numbers won’t change until I cancel and try again. So I may be able to apply them in a more blind fashion than usual. I’ve attached some crash logs here (archive.zip) but I’m not certain they’re related directly to the issues discussed in this thread.

With regards to system access, it’s a little tricky. This is my work computer, and I’m a cardiovascular biologist who spends most of his time these days in front of a variety of microscopes, with no sound, whatsoever… and we’re not supposed to install our own software. I have super-user Audacity on my PC at home, but I spend so much time on this Mac it’s just… i don’t know, i can’t be picking one up, putting another down, computers are, like, heavy… well, it wouldn’t hold up under interrogation, or, really any conscious thought, but by the time I actually have the free time and means and environment for leisure (hobby), it feels like a truly prohibitive effort to get my own computer.

I swapped up to the Retina from a MacBook Pro this Spring, and ran into some trouble with my setup, as I mentioned. A majority of plugins crash the program now, but I really can’t complain, my lonely user install has worked very well for several years; there were some plugins I couldn’t try, since they needed a system installation, but there really was a lot that could be used until [presumably] Mavericks. This wobbly playback is really starting to wear me down, so I’m going to unplug for some time, until I can re-assess. If I’m able to find anything out that may be of relevance, I’ll post it. Hope everyone has a great holiday, weekend, day, or night, depending on your inclinations. Thanks again.
Archive.zip (203 KB)

If you have any legacy software, Mavericks was the death note.

“…Adobe Illustrator is no longer supported…”

Sometimes IT will not care what you do as long as you don’t connect to the network. At one time we had special logins so guests could log into their home computers to exchange documents during meetings, for example. One of us had to supervise the connection and then they were good to go until they went home and then the connection died on its own.


Does the pitch warp occur only when you select the bluetooth speaker in Audacity or make it default system sound output (which would then affect iTunes and most other applications)?

This sounds similar to Bug 674 – Audio Unit Plug-ins don’t remember last use settings which was fixed soon after 2.0.5 was released. Can you try the latest Nightly Build from the top of http://www.audacity.homerow.net/index.php?dir=mac/&sort=date&order=desc and see if that fixes the problem?


Thanks for the crash reports.

Some of the reports don’t implicate specific plug-ins at all. Is there anything specific you do with these plug-ins to cause the crash, like using them on very long tracks or at specific settings? Or does every use of the plug-ins cause a repeatable crash?

Four specific plug-ins are mentioned in the crash reports. We can try those sometime as long as they are free and don’t require iLok.


Actually, this also happens to my Asus with Windows 10. After a successful perfect-pitched recording, after several entry into other tracks, I noticed my first entry of recorded voices warp and subtly dip in pitch. There was even an extent it sounded like a ghostly thing because of the vibratos. Haha.

Such distortions and warping added extra time to my editting since I have to creat a new trach to use as my dummy recording area and copy and paste it to the old warped sound.