Problem with playback speed control in Audacity 2.0.5

I’m running Audacity 2.0.5, EXE installer, Windows XP, and JAWS 14.0. I’m not sure if this is a JAWS problem, a bug in Audacity, or something I’m doing wrong. The playback speed control does not work like it should. If I’m playing audio, and I change the speed using the arrow keys, the control changes, but the playback speed does not. The only way I can get it to play at a higher speed is to click the Play At Selected Speed button, and I have to press Enter on it because the spacebar doesn’t work. I’ve been having this problem since Audacity 2.0.2. In previous versions before 2.0.2, I could change the speed on the fly as audio was playing without clicking the Play At Selected Speed button every time. Now, if I don’t click that button every time, the speed remains at the default.

This is noted in the Release Notes ( ):

Play-at-Speed slider: Change of playback speed is no longer automatic after you move the play-at-speed slider. To change speed, move the slider, then click the green button to left of the slider to play at the new speed.

It’s not a bug in Audacity but a bug in PulseAudio used on Linux systems. Pulse crashes if you change the Play-at-Speed slider while playing, so this ability is turned off.

This has been the case for a long time. 2.0.2 has the same issue.

Yes you have to use ENTER on the Play-at-Speed button. SPACE is for normal speed playback.

If you have not done so already, I would recommend going into the Keyboard Preferences (Command category) and adding keyboard shortcuts for “Play at speed” (which operates the Play-at-Speed button), “Adjust playback speed” (which opens the playback speed fine adjustment dialogue), “Increase playback speed” and “Decrease playback speed”. The increase and decrease shortcuts change speed by 0.03x for each key press.

The speed change still only takes effect after pressing the “Play at Speed” shortcut (or after pressing ENTER on the Play-at-Speed button), but the shortcuts should make changing speed more convenient.

You can read how to change keyboard shortcuts here: .


Thanks for the reply, Gale. Why couldn’t that feature have just been turned off in the Linux version of Audacity, and not in the Windows or Mac versions? Having to tab over to that button and click it every time is a pain.

I’m also confused about what you said about creating keyboard shortcuts. Do I, or do I not have to still click the Play At Selected Speed button if I use a keyboard shortcut to change the speed?

Because the developers wanted the same behaviour on all three platforms. I disagreed with that decision at the time, and still do, but I can see the argument. There has not been much pressure to change it, but you could write to our feedback address ( ) about it then I’ll respond there and some of the developers will see it.

Sorry I have edited one of the sentences to make it clearer.

If you only add shortcuts for “Increase playback speed” and “Decrease playback speed” then after increasing or decreasing the speed you will still have to TAB to the Play-at-Speed button and press ENTER on it.

If you also add a shortcut for “Play at speed” then that shortcut starts playback at the changed speed and you do not need to TAB to and press ENTER on the Play-at-Speed button (though ENTER on that button will still work).

Suppose for example you set F7 for “Play at speed”, F8 for “Increase playback speed” and F9 for "Decrease playback speed. Suppose you are playing a track at normal speed already and that the Play-at-Speed slider is at default 1x speed. You want to speed up to 1.3x, so without pressing SPACE to stop you press F8 ten times then press F7 to play from the cursor start position at 1.3x.


The explanation by Gale was the very brief summary version of the issue. There were multiple issues involved and crashing on Linux was the visible tip of the iceberg. The intention as with all known bugs is to fix the problem rather than to hide it.

Ideally there could be an option to save the Play at Speed setting, but even without that, once the speed has been changed a shortcut to Play at Speed will start playback at that speed and the speed is retained for the current session.

The issues (if not the fixing of them) are actually quite simple. See . PortAudio only supports Pulse through ALSA, but Pulse doesn’t support ALSA’s mixer interface, so PortAudio’s relationship with pulse is very indirect.

As it says in the bug report, what is probably required is to write a proper pulse backend for PortAudio. This might solve a lot of other problems such as the stupid bug where if the pulse devices or their aliases are selected you can’t hold down the Play or Record button for more than a fraction of a second without freezing Audacity.

The other issue is the assertion made in bug 133 by the (now inactive) developer that there is no point in fixing bug 133 without fixing the issue that changing playback speed would restart playback from the cursor position. That’s not the feedback that I get from Windows users whose workflow depends on changing speed. They much prefer changing speed to have an immediate effect, even if it doesn’t restart from current position.

There are not currently any active Linux developers capable of taking on the pulse issues involved, and so no there is no current intention to fix these issues. Thus in my opinion it would be better to re-enable immediate change of playback speed for the majority of our users rather than encourage users to stop with buggy obsolete Beta versions that still support immediate change of speed.

More than ideally. We agreed recently in Forum Crew what should happen, so I created a bugzilla enhancement issue for it: .