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
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.

Nicecast broadcasting the Loopback Pipe device
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 broadcasting the Loopback Pipe device
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:

Nicecast broadcasting the Loopback Pipe device
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
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.