Capturing streaming audio in OS X

How to grab and record “what you hear” audio on a Mac with open-source tools, using Audacity, Soundflower, and Sunflowerbed.

1. Download and install the Soundflower open-source audio routing system (which now includes Soundflowerbed application).
2. Download and install the Audacity open-source audio editing application.
3. Start the Sunflowerbed application: /Applications/Sunflowerbed.app
4. If not presented with a Sunflowerbed welcome or initial configuration screen, click the flower icon in the task bar, and beneath Soundflower (2 ch), click Built-in Output.
   

   Soundflowerbed output settings for Sunflower

5. In your system audio preferences ( -> System Preferences, Sound -> Output), select Soundflower (2ch).
   

   Sound preferences in OS X 10.6

   Note: in 10.5 (and likely earlier), the Sound panel is a bit different:

   

   Sound preferences in OS X < 10.6

6. Start Audacity, and in its Preferences, in the Audio I/O tab, under Recording, change the Device to Core Audio: Soundflower (2ch).
   

   Audacity Audio I/O settings

7. Now, anything you can listen to or stream to your system can be recorded, including Internet audio, DRM-protected content (which you’ve obviously bought but were unable to transfer to other formats), etc.
8. When you’ve finished recording, you may want to switch your Sound output setting back to Internal Speakers.