All Narfed Up photography and words by Bryan Villarin

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Update 4/18/2007: This post is outdated.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

 

7 Comments

[...] Bryan published a brief tutorial on how to increase the speed of your podcasts without altering the pitch. [...]

Posted by MacManX.com | Blogroll Dive: 6/26/06 on 26 June 2006 @ 1am

[...] Bryan Villarin picked up on that Audacity comment too, and in June 2006 posted a handy Flickr slideshow along with detailed instructions on how to use the Audacity 1.3 beta to batch these tasks to operate on a set of files all at once, saving a lot of repetitive manual steps. Thank you Bryan! [...]

Posted by Time Savers Part 1: Four Ways To Listen Faster | Groundhog Day on 9 February 2007 @ 8am

Hi are you using a MAC? The screens I see look quite different from yours and I don’t see a Process Batch command.

Posted by CM on 17 March 2007 @ 7am

@CM: Nope, Windows XP.

Posted by Bryan on 17 March 2007 @ 12pm

[...] myself reciting the 34 vocabulary words, which needed to be memorized word for word. Then, I sped up the tempo in Audacity (which doesn’t change its pitch), added a split-second Sine chirp between terms, then [...]

Posted by Lessons learned from a studying frenzy at All Narfed Up on 12 April 2007 @ 12pm

This article needs to be updated for Audacity 1.3.2 (Beta). Comments closed, update will be posted within a few days.

Posted by Bryan on 18 April 2007 @ 8am

[...] How to speed up podcasts for free with Audacity (v2) Published April 18th, 2007 in School, iPod, Open Source, How-to and Podcasts. Tags: audacity, audio files, batch script, change tempo, class lectures, podcasts. Tags: audacity, audio files, batch script, change tempo, class lectures, podcastsThis is an update to the How-to article, “How to speed up podcasts for free with Audacity.” [...]

Posted by How to speed up podcasts for free with Audacity (v2) at All Narfed Up on 18 April 2007 @ 2pm