Tutorial - Recording Computer Playback on Mac

ToDo-2 Ready for Proofreading Peter 2Aug11

• needs a Mac user to review it.

Mac computers have no ability to record streaming audio as it plays on the built-in sound device; you will have to either employ a loopback cable or use some alternative software for the audio capture, in this case the resulting file should be capable of being imported into Audacity for further processing.

Gale 08May11: I know we don't want to get too complex but I would have thought an important point was not recording system dings. For that I think we have to say that SoundFlower is preferable and say a bit more about how to use it to record the sound only from a particular app. (where an app lets you choose its output device). I take it iTunes doesn't let you choose even on Mac?
Bill 08May11: Actually, even using SoundFlower you will record system dings. AFAIK no applications on Mac allow SoundFlower to re-route their sound output. For that you need Audio Hijack Pro.

• Gale: OK. I was assuming the Soundflower blurb had some validity: "To send the output of one application to another, select Soundflower as the output device in the first application and Soundflower as the input device within the second application."
• Bill: That's possible as long as the app allows you to select it's audio output device, which very few do. Certainly not Safari, Camino or Firefox. If you go to YouTube and search for "Routing audio in CamTwist via Soundflower" you'll see one instance where this can be done. Another thing that video shows is the use of Soundflowerbed to allow monitoring through the computer speakers even when the computer audio output is routed through Soundflower - I've now added that.

Use a loopback cable

This is a simple and effective method of recording what is playing on the computer. It has the disadvantage that the audio signal is converted from digital to analog, then from analog to digital, instead of staying in the digital domain. This may result in some slight increase in noise and distortion.

• Using a cable with a stereo mini-plug (1/8") at each end, connect the headphone output port to the line input port.
  • You will now no longer have any sound coming from the computer speakers.
• Go to Apple Menu > System Preferences and select the Sound preferences panel.
• In the Sound preferences panel:
  • Click on the Output tab, then select "Line Out" from the "Choose a device for sound output" list.
  • Click on the Input tab, then select "Line Input" from the "Choose a device for sound input" list.
  • Leaving the Sound preferences panel open, start sound audio playing on the computer (this could be from iTunes, or streaming audio, or some other source)
  • Adjust the Input volume slider so that the top 3 bars of the Input level meter do not light up on the loudest passages, but the rest of the bars do light up.
• Close the System Preferences window.
• In Audacity's Device toolbar select "Built-in Audio: Line in" as you chosen Input Device
  
  

Note that you still will not be able to hear what is playing on the computer until you start Audacity and turn on monitoring.

Also note that any "system dings" will be recorded using this method. If you have iCal alerts or have turned on event sounds in Apple Mail, you may want to turn them off.

Use Soundflower

Soundflower is a free open source system add-on for Macintosh that allows you to route what is playing on the computer digitally back to the input without using a cable.

You need to set Soundflower as your default output device. In Audacity, you then set Soundflower as your input device.

• Download and install Soundflower from the Soundflower web site. As of May 2011 clicking the download link on the Soundflower site will take you to the Google code hosting page. On the left there is a panel with the heading "Featured", then a "Downloads" heading, then a list of links. Unless you have an Intel Mac running 10.5.8 or later, click the "Show All" link, then choose the version of Soundflower for your Mac and version of OS X.
• Go to Apple Menu > System Preferences and select the Sound preferences panel.
• In the Sound preferences panel:
  • Click on the Output tab, then select "Soundflower (2ch)" from the "Choose a device for sound output" list.
    • At this point you will no longer be able to hear what is playing on the computer. The sound output of the computer is being sent to Soundflower.
• Close the System Preferences window.

Note that any "system dings" will be recorded using this method. If you have iCal alerts or have turned on event sounds in Apple Mail, you may want to turn them off.

To hear what is playing on the computer while using Soundflower

When you install Soundflower, and new folder will be installed in your Applications folder called "Soundflower". Inside the folder is a program called "Soundflowerbed". Launch Soundflowerbed: it will install a "flower" menu at right of your menu bar.

The choices below the "Soundflower (2ch)" and "Soundflower (16ch)" menu items determine how the output of Soundflower will be monitored. "None (OFF)" means that you will not hear anything from your computer speakers. Selecting "Built-in Audio" will allow you to hear (monitor) the sound that is passing through Soundflower.

• In Audacity's Device toolbar select "Soundflower (2ch)" as you chosen Input Device
  
  

If you are using Soundflowerbed to monitor the sound, you will want to uncheck "Software Playthrough" in the Transport menu.

Audio Hijack Pro

This is a commercial program sold by Rogue Amoeba. It can "hijack" the sound output of any program and record that audio to disk in a number of formats. The advantage is that "system dings" will not be recorded. Once you have captured the audio with Audio Hijack Pro you can import the file into Audacity for editing.

If you need help editing the audio captured by Audio Hijack Pro, have a look at our tutorial on editing an existing file.

Links

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