Capturing audio from hidden sources

Starting with version 2.0, Loopback makes it possible to capture audio from background processes which do not appear on your Mac like traditional applications. Herein, we refer to these processes as “hidden sources”, and they include system services, as well as the occasional command-line tool.

Accessing Hidden Sources

By default, these hidden sources are not listed in Loopback's “Add Source” menu. By holding down the Option key when clicking on the Add Source button, a new menu item will be shown, “Running Processes”. Within the Running Processes sub-menu, you'll see a list of processes from which Loopback could conceivably capture audio.

A note for VoiceOver users: To access the Running Processes sub-menu, hold down the Option key and press the space bar while the Add Source button is selected, rather than using the VO-modifier key.

Useful Hidden Sources

When viewing the Running Sources menu, you're likely to see dozens of different processes. Only a few of these produce audio.

Capturing Spoken Dialog

The most common hidden sources users wish to capture are Siri, Text to Speech, and VoiceOver. While sources with these names may appear in the Running Processes menu, selecting them is not likely to provide the desired audio.

Instead, to capture audio spoken by Siri, Text to Speech, or VoiceOver, you must select the “com.apple.speech.speechsynthesisd” hidden process.

This single process provides the spoken dialog audio for Siri, Text to Speech, and VoiceOver. By selecting it, you can capture Siri's spoken response, the OS's built-in Speech commands (triggered by the “Start Speaking” command in the Speech menu), and VoiceOver's accessibility hints.

Capturing Sound Effects With Spoken Dialog

If you wish to capture the sound effects used by Siri or VoiceOver, you'll need to capture other hidden sources.

Siri: The “assistantd” hidden process is the source of Siri's sound effects.

VoiceOver: The “VoiceOver” process is the source of VoiceOver's sound effects.

Capturing Audio from Parallels Desktop

When you're running a virtual machine in Parallels, you'll see two visible Parallels processes (“Parallels Desktop” and a second process named for your specific virtual machine). However, neither of these process

Instead, to capture audio, you must select the “Parallels VM” hidden process. This is the true source of from your Parallels virtual machine.

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