loopback
If you wish to use an audio recorder to record audio being played by another application, such as capturing audio from youtube, you can use a loopback driver.
An Audio Loopback Driver is a virtual driver that allows one software to capture audio from another software. This is an alternative to capturing from a microphone. Simply holding a microphone up to your speaker would do a poor job of audio capture.
3rd Party Loopback Audio Virtual Devices/Drivers
- Blackhole - free full version seems to be the best option as of 2023
- Background Music
- Rogue Amoeba Software: Loopback - trialware, pay software $99 (ouch)
-
iShowU is no longer supported
Example loopback virtual driver for MacOS
- BlackHole - Route Audio Between Apps (BlackHole v0.2.6 virtual audio driver from GitHub)
It does not appear to be in the Apple Store. It is on GitHub.
Another possible option as a loopback is "Background Music"
Blackhole
BlackHole is a modern macOS virtual audio loopback driver that allows applications to pass audio to other applications with zero additional latency.
To record the mac's internal sound with Quicktime you need additional software. You can use the free BlackHole Virtual Audio Driver and choose "BlackHole 2ch" in the recording options instead of "Built-in Microphone."
capture
You can now capture and record with the latest version of Apple Quicktime. You will still need a loopback driver to capture from another software application.
- In the QuickTime Player app on your Mac, choose File > New Audio Recording.