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Update 4/18/2007: This post is outdated.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.

However:

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.

• What you’ll need: Audacity 1.3 Beta
• Difficulty: Moderate
• Time: Configuring the batch script – 1 minute; increasing the tempo of the podcasts – varies, depending on the number of podcasts being processed

First, you have to configure the batch script. In Audacity, navigate to Edit > Preferences.

Then, navigate to the podcast folder in your iTunes Library. Copy the fresh podcasts into the root podcast folder (for easier conversion).

Now, in Audacity, go to File > Process Batch. And then:

After the podcasts are done processing, switch back to the Explorer window. Inside the Podcasts\cleaned folder, move the MP3s up a folder, then into their respective Podcast folders (overwriting the ones already in there).

Lastly, go back into iTunes and update the Podcasts. (Right-click each one, then choose “Get Info”.) You should notice that the length of each one shrinks.

I take an extra step of adding an asterisk before the title of the podcast to denote that I already increased the tempo.

Conclusion: For someone who gets overloaded on podcasts sometimes, the slight increase helps a lot. My podcast folder is like another Inbox. It’s not like it’s a hassle to listen to podcasts, but sometimes you really do want to get through it and every little bit helps.