Instructions for:
Working with audio from special and hidden sources

In addition to adjusting audio from traditional applications, SoundSource can adjust audio from certain special sources, as well as hidden background processes which do not appear on your Mac like traditional applications. This includes system services, as well as the occasional command-line tool.

Choosing special sources

SoundSource's Add Favorite menu makes it easy to choose popular sources which would otherwise be very difficult to find. This is done through the Special Sources section of the Add Favorite menu, where you can choose:

  • Finder
  • System AirPlay Receiver
  • System Speech

The Finder special source

Choosing the Finder special source will allow the capture of any audio played by Finder.app, as well as by the hidden “QuickLookd” process (or the hidden quicklookd process on MacOS 10.13 and lower), which plays audio when using the Mac's “Quick Look” functionality.

The System AirPlay Receiver special source (MacOS 12 and newer)

The System AirPlay Receiver special source captures audio played directly to MacOS via AirPlay, using the system's AirPlay receiving capabilities. If you're streaming audio to your Mac via AirPlay, you can capture it in with the System AirPlay Receiver special source.

For more robust AirPlay receiving on your Mac, we recommend Airfoil Satellite.

The System Speech special source

The System Speech special source makes it possible to capture audio spoken by MacOS. This source will capture audio spoken by Siri, Text to Speech, and VoiceOver. It will also capture sound effects from both Siri and VoiceOver.

With the System Speech special source, multiple processes will be captured. Foremost is the powerful com.apple.speech.speechsynthesisd process, which provides the spoken dialog from Siri, the system's text reading (triggered by the Start Speaking command in the Speech menu), and the accessibility hints spoken by VoiceOver. In addition, Siri's sound effects are captured the assistantd hidden process, and VoiceOver's sound effects are captured from the VoiceOver process.

In SoundSource, Siri, Text to Speech, and VoiceOver have been merged together to form one special source due to the way the system provides their audio. Do note that any adjustment you make to this special source will affect audio from all of these sources.

Accessing other hidden sources

By default, other hidden sources are not shown by SoundSource's Add Favorite menu. However, if you hold down the Option key when clicking on the selector, a new Running Processes sub-menu will be shown. Within the Running Processes sub-menu, you'll see a list of processes from which SoundSource may be able to capture audio. While the Running Sources menu will show dozens of different processes, only a few of these are likely to produce audio.