The Loopback Pipe Device
The Loopback Pipe is a special device that enables you to send audio directly between applications, with no additional configuration in Loopback required. Loopback Pipe will appear on the system as both an audio output and an audio input. Just feed audio into Loopback Pipe from any application with an audio output selector, then set Loopback Pipe as your audio input device in another application to receive that audio.
Loopback's Pipe device
While Loopback Pipe will work without additional configuration, note that you can add and remove channels from it for advanced usage. You can also disable the device, by turning off its checkbox in the main list.
Feeding Audio into Loopback Pipe
To feed audio into Loopback Pipe, select “Loopback Pipe” from the audio output selector inside the desired source application.
Audio Hijack setting Loopback Pipe as an audio output device
Pulling Audio out of Loopback Pipe
To pull audio back out from Loopback Pipe, just select “Loopback Pipe” as the audio input inside the desired source application. Now any audio being sent to Loopback Pipe will be pulled in by your application.
Nicecast selecting Loopback Pipe as its audio input
Example Usage
The Loopback Pipe device makes it easy to move audio between applications, and it can be used in many different ways. Below, you can see an example of Loopback Pipe in action. As a podcast is being recorded, the Loopback Pipe device is making it easy to simultaneously live stream that audio to listeners on the Internet:
Audio Hijack passing audio to the Loopback Pipe device
This example uses Audio Hijack to capture audio from several sources: a microphone for local audio input, Skype for remote audio input, and iTunes for background music. In addition to being recorded, that audio is all sent to an Output block, where the Loopback Pipe device has been selected.
Nicecast broadcasting the Loopback Pipe device
To provide the live stream for listeners, Nicecast is used. Above, the Loopback Pipe device has been selected as an audio input in Nicecast's Source drawer. Now all the audio that's being sent into Loopback Pipe will be passed out to the broadcast.