Speed Adjustment Problem

I have a problem with Audacity v2.0.6 (I think I got Audacity as a dmg file, but I’m not 100% sure). I am running Audacity on a 27" iMac running 10.6.8 (Intel Core i7 with 12 GB RAM). I have some really old 45 RPM records that I am digitizing using a cheap turntable with a USB output. I am capturing the music just fine, except that the turntable plays 7% fast at the 45 RPM speed. If I use the Playback Speed control on the far right of the Audacity toolbar and change the speed from 1.0 to 0.93, Then everything is perfect. The issue is that when I export the file to a 256 Kbps MP3, that speed correction is not in the exported MP3. Same thing if I choose Effect → Change Speed… and enter 0.93. The effect is evident in the Audacity native format, but gets lost when I export to an MP3. My original audio is being captured at 44100 Hz, 32-bit floating point.

Can anybody offer a suggestion about how to make the speed change remain in effect in an exported file (either via the toolbar Playback Speed or via Change Speed in the Effects menu)? I’m sure it’s just something dumb that I’m doing, but I can’t find anything in the documentation that addresses this issue. Thank you in advance for your help!


I think I see. You are using the Audacity live playback speed control which has the effect of dragging your finger on the record, but the basic song doesn’t change. If you want permanent speed shifts, use the effect.

Select the song by clicking just above the MUTE button.
Effect > Change Speed.

Then Export.


If you did Effect > Change Speed then entered 0.93 then you were changing the speed by 0.93% - hardly at all. Try entering -7 into the effect.
Make sure you have reset the transcription toolbar back to 1.0.

Yes, speed changes made using the transcription toolbar are not exported.

– Bill

Bill and Koz, thank you for the quick replies and suggestions.

Koz, I did find the solution, and your suggestion is the closest to what I found. The Change Speed item under Effects is what I used to solve the problem (I set it to -7.0%), but there seems to be slight wrinkle. If I have the native file opened in Audacity, apply the Change Speed effect, it will play at the correct reduced speed in the native Audacity format, but if I export the file as an MP3, the speed change is not included in the exported file unless I first save the Audacity Project. Then the exported file does play at the correct speed. Never seen an application behave like this!

Billw58, your statement that the changes made with the transcription toolbar are not exported, no matter what I do is correct. One correction that I’d like to make is that while the Change Speed effect is based on percentages (-7.0 is what brings the pitch and speed back to normal), since “normal” speed is represented by 1.0 by default in the transcription toolbar, by putting in 0.93, that is a 7% reduction and in fact gives the same result as entering -7.0 in the Change Speed dialog. Interesting that Audacity does not use a consistent method of defining the speed.

A suggestion I would make for a future version of Audacity would be to have a checkbox (or something similar) that would allow you to enter either the percentage directly in both methods of adjusting the speed, or enter a fraction as you do now on the transcription toolbar. That would provide a degree of consistency in the user interface that would be appreciated. I would also like to see whatever gremlin is at work that does not allow the Change Speed effect to export to an MP3 unless the project is saved before the export occurs to be addressed.

On an unrelated note, has anyone tried the paid application “ClickFix” which is supposed to do a great job of removing ticks and pops from recordings without affecting the quality of the recording (within reason). It has gotten some excellent feedback. I was wondering how this compares with the quality of the Click Removal and Noise Removal effects in Audacity?

Thanks again to both of you!

No. If you did it correctly the result of Change Speed is exported whether you save the project or not. Perhaps you undid Change Speed by accident.

If you update to the current Audacity 2.1.0, there is a “Speed Multiplier” box where you could enter 0.93 for the -7% change.


Gale, thanks for the reply and suggestions. This is very interesting. I am able to duplicate the issue where the Change Speed effect works when I use it on a music file in the native Audacity format, but it gets lost if I export the music file to the MP3 format without saving the project first. If I do that, all is happy. I will try this again after I update to Audacity 2.1.0.

Your next suggestion that I update to Audacity 2.1.0 made me take another look at the system requirements. I originally stayed with version 2.0.6 because I thought I read that newer versions were not compatible with MacOS X 10.6.8. Now, based on your post, I went back and reread the system requirements and it does clearly state that this version of the MacOS (Snow Leopard) is compatible with Audacity 2.1.0. I hate when I make dumb errors like that :blush: . Thanks for pointing this out to me. I just downloaded that version and ffmpeg version 2.2.2 just in case that plug-in does not remain after I update Audacity (although I’m pretty sure that it will). I’ll actually install it later today.

BTW, I accidentally referred to a program called ClickFix in my previous reply. That was also incorrect because the name of the program is ClickRepair (http://www.clickrepair.net/). I’ve read really good things about this program and this is what I was looking to compare to Audacity’s Noise Removal and Click Removal effects.


If that is the case then the exported file would be too short and high pitched. I find it hard to believe that, but is that what happens?

FFmpeg does not need re-installing if you previously had 2.0.6.

See https://forum.audacityteam.org/t/click-pop-removal-clickrepair-software/1933/1