How to speed up podcasts for free with Audacity (v2)

This is an update to the How-to article, “How to speed up podcasts for free with Audacity.”

In Audacity 1.3.2 (Beta), configuring the batch script is easier. The developers moved the location, though, so you might be lost if you recently updated to this version.

First, setup the chain: File > Edit Chains

In the left pane of the window that pops up, you’ll need to add a new chain. Title it “Speedup,” or whatever you like. With it selected, the right pane should have only one parameter: END.

Select that command, then at the bottom of the window, click Insert. Another window will pop up, and you’ll want to choose Change Tempo. Change the parameter to 25.000000, then click OK. (Later, you can increase the tempo if you’re comfortable.) Again, click Insert, select the ExportMP3 command, then click OK. Finally, OK out of the Edit Chains window.

Then, if you want to run the script, go to File > Apply Chain. Select the chain you just created, click Apply to Files, then browse to the folder where the podcasts are stored. Like I mentioned in the previous How-to, I copy the MP3s to the root podcast folder, so I’m not limited to one show (folder) at a time.


This’ll empower you to listen to podcasts, or any other supported audio files in a shorter amount of time, and you can convert multiple files at once. In addition to podcasts, I also speed up class lectures. 80-minute classes reduced to 64 minutes — awesome!

How to speed up podcasts for free with Audacity

Update 4/18/2007: This post is outdated. Audacity 1.3.2 (Beta) changes the method a bit, which I describe here.

Over a month ago, Lifehacker linked to an article: “Speeding Up Podcasts and Audio Books“. Here are the two sentences that caught my eye:

It lets you play one minute and fifteen seconds of audio for every minute you listen. In other words, you get an extra 25% of content.


It’s the feature that Apple introduced with the 4G iPods back a couple of years ago. The feature is the ability to speed up (or slow down) audio without changing the pitch (if you are familiar with variable speed tape recorders, you understand that simply speeding up the playback of something tends to also make the speaker sound like a chipmunk).

I have a 3G iPod, so I don’t have this feature. The article mentioned Amazing Slow Downer, but it’s not free. Fortunately, Matt commented about Audacity:

Audacity is great for this, at an unbeatable price ($0). [..] It is cross platform, open source (free), and [speeds] up audio excellently, [in addition to] being a general purpose audio editor. There was a beta of the next version last time I checked that allowed bulk conversion. Unfortunately no command-line. (Effect [menu] > Change Tempo is the command you want.)

So, if I want to speed up podcasts, I have to do some work. Except for the tempo increase, it won’t be automatic.

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