Welcome to Loopback

Loopback gives you the power of a high-end studio mixing board right inside your computer, making it possible to route audio between applications with no physical wires required. Now you can control exactly how and where audio is heard on your Mac.

Getting Started

This manual provides you with a useful overview of the application, including an outline of the interface, as well as details on using the application. We recommend a quick read-through, but you can also just dive in if you like. Refer back to this online manual for assistance at any time, right from Loopback's Help menu.

Additional Assistance

The following resources will supplement a read-through of the manual and help you get the answers you need.

Information for Users of Previous Versions

If you've used Loopback before, this information should prove helpful.

Device Basics

With Loopback's virtual audio devices, you can route audio around your computer in powerful new ways. These virtual devices appear throughout your system in the same way as physical devices, like microphones or speakers do. Let's begin by discussing the basics of how virtual audio devices work.

Loopback at Startup

Loopback's main window at initial launch

Loopback has a single main window which lists all of your current virtual audio devices in the device list on the left side. When you first launch Loopback, you'll see the Loopback Audio device. This default device is automatically created and enabled when you first install Loopback.

Creating and Deleting Virtual Audio Devices

Controls for adding and removing virtual audio devices

To create a new virtual audio device, just click the (+) New Virtual Device button in the lower left corner of Loopback's main window. When you do, a new device will appear in the device list, already enabled and ready for further configuration as desired.

To delete a virtual audio device entirely, highlight it in the list, then click the (-) button. Note that device deletion can't be undone. You can, of course, create a new device.

Rather than permanently deleting a device, you may instead wish to temporarily disable it.

Adjusting the Device Name

To adjust a virtual audio device's name, click the device in the Devices list on the left side of Loopback's main window to select it. Once the device is selected, you'll be able to edit its name at the top of the Device Editor area on the right side of Loopback's main window. Click the Edit pencil, then type the new name, and press Return or click away to finalize the change.

The Name field for a Loopback device

This name affects how the device will appear in audio input selectors throughout the system. Note that some applications may not immediately detect the new name. Toggling the virtual audio device off then back on in Loopback should cause the new name to be shown everywhere. If the old name still persists in an application, quit and relaunch that app to get the new device name to appear.

Enabling and Disabling Virtual Audio Devices

The “iTunes & Mic” device is enabled;
The “Loopback Audio” device is disabled

Newly created virtual audio devices are enabled by default, so that they can be used immediately. To disable a device, toggle the On/Off switch next to its name in the device list. To re-enable the device, toggle the slider back on.

It may be useful to think of disabling a virtual audio device as the equivalent of unplugging a physical device from your computer. Likewise, enabling a virtual device is the equivalent of plugging a physical device into your computer.

Set It and Forget It

The Loopback application does not need to be running for your virtual audio devices to appear throughout the system. Once you’ve created and configured things in Loopback, you can quit the app. The virtual audio device will persist, even across machine restarts.

Configure Your Devices

Next, learn how to configure your devices by reading the three pages in this manual's “Device Configuration” section. You'll see how to set which audio sources a virtual device pulls in, as well as how to adjust the number of output channels it has (as well as how they're configured), and how to optionally monitor audio coming through the virtual device.

Device Configuration

Sources

Virtual audio devices can be used as simple pass-thru devices, but Loopback provides much more power by allowing you to configure audio from specific sources to flow through a device. This is done in the Sources column of the Device Editor.

The Sources column in its default state

When a device is created, it will contain only the special Pass-Thru source. This allows audio to enter the device as input and be passed out as output, which allows audio to be piped directly between applications without any further configuration needed in Loopback. For more details on Pass-Thru, see the Notes on Pass-Thru page.

For more control, you can configure your virtual audio device to pull in audio from specific audio sources (both applications and physical devices). To add a source to a device, click the (+) button at the top of the Sources column, then select an application or audio device. Any audio produced by the source will then be included in the virtual audio device’s output.

Below, you can see that we've added the software application iTunes to our device, as well as a USB microphone.

The Sources column, with audio sources added

Thanks to Loopback, the audio from all these sources will be combined into one virtual device.

Additional Settings

On/Off Toggle

The “iTunes” source is on, while the “USB Mic” source is off

Using the On/Off switch, you can toggle an individual audio source off. This enables you to temporarily exclude the source's audio from the virtual device without deleting the source and losing its configuration.

Volume Sliders

A source's volume slider

All source types (Applications, Audio Devices, and Pass-Thru) offer a volume slider under the Options area. In general, leaving these at their default 100% level is best. If desired, you can use these sliders to adjust the relative level of audio provided by the source, as it compares to other sources in the virtual device.

A source's volume slider while muted

The speaker indicator to the left of the volume slider can act as a mute switch. Click it to mute the source, without affecting the volume setting. This can be used to temporarily prevent the source's audio from being included in your device.

Mute checkbox

An application's “Mute when capturing” checkbox

Application sources feature a second setting in their Options area: the Mute when capturing checkbox. This checkbox is on by default, which means that when the virtual audio device is in use, audio from the application source will not be played through. This is usually desirable, as applications using the Loopback virtual audio device will frequently want to perform their own audio play-through, after some amount of processing.

In most cases, you'll want to leave this checkbox in its default On state. However, if you want the audio from an application source to be audible regardless of how the virtual device is being used, you can toggle the checkbox off.

Removing a Source

To remove an audio source from your virtual device, click on it in the editor to highlight it, then click the Delete button in the bottom bar or select Delete from the Edit menu.

Channel Mapping

By default, Loopback maps sources to output channels automatically. For details on adjusting this mapping, read over the Output Channels page.

Output Channels

Physical audio devices usually have two or more channels, each of which can carry distinct audio. For example, a stereo microphone has both left and right channels, while more complex mixers may have 8, 16, or even more channels. Loopback's virtual audio devices start as 2 channel stereo devices, but they can be configured to have up to 64 channels.

Loopback handles some channel mapping automatically. When you add a source or monitor to a virtual device, its channels will be mapped one-to-one with the device's existing output channels, as possible. Similarly, when additional output channels are added, the Pass-Thru source is updated and auto-mapped to them. Note that mappings for application and audio device sources, as well as monitors, are not automatically modified when output channels are added.

Manually Adjusting the Channel Mapping

Below, you'll see the automatic channel mapping for our device with iTunes and a USB microphone (for clarity, the Pass-Thru source has been removed). This automatic mapping will often be sufficient, but it's also possible to manually configure the virtual audio device's channel mapping, via the Output Channels column.

A default channel mapping

Adding Output Channels

As mentioned above, virtual audio devices initially have two channels. Using the (+) button next to the Output Channels column header, you can add channel pairs, up to a total of 64 channels.

A second pair of outputs has been added, but nothing maps to it yet.

Re-Wiring Audio Flow

Once your device has the desired number of channels, you can use the intuitive wiring system to configure your audio routing exactly as desired. To add a connection, click and drag from one wiring socket to another. As shown below, a wire will be drawn to visually demonstrate that a connection has been established.

Channel wiring, in action

Below, you can see that channels from iTunes and the USB mic have been manually mapped to four output channels.

A fully configured channel mapping

In this setup, audio from the physical microphone's audio will be heard on channels 1 & 2, while iTunes audio will be heard on channels 3 and 4. Custom setups like this make it easy to record audio to distinct tracks, just based on the channels selected in your recording application.

Removing Output Channels or Wiring

To remove a channel pair from your virtual device, click on it in the editor to highlight it, then click the Delete button in the bottom bar or select Delete from the Edit menu.

Removing a connection between a source and an output channel, or between output channel and a monitor, is performed in similar fashion. Click the wire you wish to remove to highlight it, then click the Delete button in the bottom bar or select Delete from the Edit menu.

Monitors

Loopback devices can also be configured to include monitors, allowing you to use a secondary audio device to hear how your virtual device will sound. For details see the Monitors page.

Monitors

Monitors

Using the Monitors column, you can optionally direct audio from your virtual device to play through a secondary audio device. This can be useful for monitoring how your virtual device will sound to others.

By default, Loopback's virtual audio devices do not include any monitors. To add a monitor to a virtual device, click the (+) button at the top of the Monitors column, then select an audio device.

Below, you can see that we've added a monitor called “Built-in Output”. As a result, audio from the virtual device will now be heard through the monitor device.

A monitor device in its default configuration

Manually Adjusting the Monitoring Configuration

When a new monitor is added, Loopback will automatically map output channels to it, on a one-to-one basis, as possible. Any audio produced by the source will then be included in the virtual audio device’s output.

You can also modify this wiring manually, using the same techniques described on the Output Channels page.

Manually configured monitors

Additional Settings and Notes

On/Off Toggle

The “Built-in Output” monitor is on.
The “USB Output” monitor is off.

Using the On/Off switch, you can toggle an individual monitoring device on or off, adjusting what you hear as needed.

Volume Sliders

A monitor's volume slider

Monitors offer a volume slider under their Options area, enabling you to control the volume level audio at which audio is heard.

A monitor's volume slider while muted

The speaker indicator to the left of the volume slider can act as a mute switch. Click it to mute output to the monitor, without affecting the volume setting. This can be used to temporarily prevent audio from being sent to the monitor.

Muted Application Sources

When a virtual device includes a monitor, it will be activated whenever ones of its sources is providing audio, even if no other application is using the device. This will in turn cause the Mute when capturing setting for application sources to apply. As a result, audio may not be heard through the Mac's default output, but would be heard through the monitor device.

Removing a Monitor

To remove a monitor from your virtual device, click on it in the editor to highlight it, then click the Delete button in the bottom bar or select Delete from the Edit menu.

Device Usage

When you've fully configured your virtual device, the Using Virtual Devices page offers more information on using it on your Mac.

Using Virtual Devices

This page details how to use your virtual audio devices with other software on your Mac.

Selecting Virtual Audio Devices on Your System

Once a virtual audio device is enabled in Loopback, it's immediately ready for use by any application. You'll see the device in the Sound System Systems, under both the Output and Input tabs, as pictured here:

A Loopback virtual audio device in the Sound System Settings

The virtual audio device will also appear in the device selectors for any audio applications which offer them. You'll be able to select the device as an audio input in Skype, FaceTime, GarageBand, and many other applications.

A Loopback virtual audio device selected in Zoom's settings

Adjusting Device Sample Rate

The initial sample rate for a newly created Loopback virtual audio device is determined by the system's current default output device. This sample rate can be changed at any time. This can be useful with higher fidelity audio, as increasing the sample rate is the only way to ensure the entire audio flow will not contain any lossy conversions.

To change the sample rate of an enabled Loopback virtual audio device, open MacOS's Audio MIDI Setup application (located in the Utilities folder of your Applications folder). Here, you can change the sample rate exactly as you would for an actual hardware audio device. Your Loopback virtual audio device will remember its new sample rate, even if it is later disabled and re-enabled.

Changing the virtual audio device's sample rate in Audio MIDI Setup

Notes on Pass-Thru

Loopback virtual audio devices have the ability to function as both audio inputs and audio outputs. While all virtual devices will appear as inputs, the ability to appear as an available output is accomplished with Loopback's Pass-Thru source. Appearing as an output device makes it possible to pipe audio directly between two applications. We refer to devices doing this as “pass-thru devices”.

Some users may have previously used the tool “Soundflower” for similar audio routing between applications. Loopback modernizes the necessary infrastructure, providing a reliable method of passing audio directly between applications.

Creating a Simple Pass-Thru Device

Any Loopback virtual audio device can function as a pass-thru device, as long as the Pass-Thru source is present and enabled. When you make a new Loopback virtual audio device (by clicking the New Virtual Device button), the Pass-Thru source is automatically included. If you like, you can rename the device to something like “Pass-Thru”, as we've done here. That's the extent of configuration that's required inside of Loopback.

A simple pass-thru device

This pass-thru device will appear on the system as both an audio output and an audio input. Any application with an audio output selector can feed audio into the pass-thru device, while any application with an audio input selector can pull it out.

Adding Audio to the Pass-Thru

To add audio to a pass-thru device, select it from the audio output selector inside the desired source application. Below, we sent audio into the device by adjusting an Output block in our audio recording tool Audio Hijack.

Audio Hijack setting “Pass-Thru” as an audio output device

With this setting, audio from the Audio Hijack Session in question will be sent into the pass-thru device.

Receiving Audio From the Pass-Thru

To receive audio from the pass-thru device, just select “Pass-Thru” as the audio input inside the desired source application. Now any audio being sent to “Pass-Thru” will be pulled in by your application.

Zoom selecting “Pass-Thru” as its audio input

Above, we've set the VoIP app Zoom to pull audio out of the pass-thru device.

Adjusting the Channel Count

When you add output channels to your Loopback virtual audio device, the Pass-Thru source will automatically gain channels as well. Those channels will be mapped one-to-one to the output channels, automatically. In this way, your virtual device will be able to take in up to 64 channels of input, and pass it through to 64 channels of output.

A Pass-Thru device with 4 channels

It's unlikely you'd want anything but a one-to-one mapping of inputs to output channels, but do note that you can remove and reconfigure channel mappings if you desire.

Removing and Adding Pass-Thru Functionality in a Virtual Device

When a new Loopback device is created, it includes the Pass-Thru source by default. With this source on, the device will appear as an output device, as well as an input device.

If you don't want a device to appear as an output on your Mac, you can toggle the Pass-Thru source off, or delete it entirely from the device.

If you wish to restore a device's ability to be an output, just toggle the Pass-Thru source back on, or re-add it using the Add Source menu at the top of the Sources column.

The Pass-Thru Source in Other Virtual Devices

It's generally best to use a Loopback virtual audio device as either a pass-thru, with no other sources, or as a fully configured device which skips the pass-thru functionality. Using your Loopback virtual audio devices in one of these two ways is the best way to avoid any confusion as far as your audio routing goes.

A Pass-Thru device

A fully configured device

That said, Loopback doesn't prevent you from using the Pass-thru source alongside other configured audio sources. If you do, audio from the included sources will be pulled into the Loopback virtual audio device. If any other application has the Loopback virtual audio device set as an output, that application's audio will flow into the device as well.

Settings (née Preferences)

Loopback's settings can be accessed from the Loopback menu.

Loopback's Settings window

Appearance

Theme Selector: This setting dictates how Loopback will appear. The Light theme is designed for everyday use, while the Dark theme is perfect for use in darkened spaces like studios and theaters.

The default Match System setting follows the OS-wide Appearance setting for Light or Dark Mode. You can alternately force Loopback to use the Light or Dark theme, regardless of your system-wide settings.

Loopback's Light theme


Loopback's Dark theme

While this manual uses the Light theme throughout, you can easily try either theme. Loopback will update immediately when you adjust this setting.

Software Update

Automatically check for software updates: With this option activated, Loopback periodically compares itself to the most current version available from our server and alerts you when a new version is available. Leave this on and Loopback will help you stay up-to-date. You can also select Check for Update from the Loopback menu to initiate a check manually.

To initiate a check manually, click the Check for Updates… button.

Purchasing

Quick Link: Visit our online store to buy a license key for Loopback.

Why should I buy Loopback?

Put simply, you should buy Loopback because it isn't free. We provide a free trial, so you can test out the program and all its features before you buy it. It's like test driving a car, for as long as it takes you to decide.

In trial mode, all of Loopback's features are available to sample, but it won't work for full-time use. During the trial, the quality of audio passing through Loopback's virtual audio devices will be degraded after twenty minutes.

If you use Loopback and find you like it, please purchase a license key - support the software you use and love!

To purchase your license key, just visit https://rogueamoeba.com/store/.

What about upgrades?

If you purchased a license for Loopback before September 1st, 2018 (your license key will start with CIRC-), you're eligible for a discounted upgrade to version 2.

Read about what's new in Loopback 2 on our site, then purchase a heavily discounted upgrade.

Note: If your license key starts with VADS-, you already own Loopback 2 - enjoy!

After Purchase

How do I unlock the full version?

The download of Loopback from our site contains both a free trial of the software and the full version. To unlock the full, unlimited version, you just need a valid license key. When you purchase through our store, you'll immediately receive a license key in your browser. It will also be sent to you via email. Simply enter this key into Loopback to unlock it.

What's your upgrade policy?

While we don't have a hard and fast upgrade policy, our philosophy regarding paid upgrades is simple: We try to do what's right for you and what's right for us. We've got a great track record, with many years of very satisfied customers.

For more details on free updates and paid upgrades, please see this page.

What's your refund policy?

All Rogue Amoeba products are available to try before you buy. We believe that no customer should have to buy software in order to find out how well it works. Our software can be fully evaluated with no limitations in capabilities, prior to purchase. Customers are strongly encouraged to take advantage of these trials prior to purchase. You may also seek any needed technical support from us - we answer support emails rapidly and responsively for current and potential customers alike.

If you would like a refund, please contact our Support Team within 14 days of your purchase. Because we cannot recover the license key that was sold, refunds are issued on a case-by-case basis.

Etcetera

Installing & Uninstalling

Installing Loopback

To install Loopback, drag it from your download folder to the Applications folder, then double-click its icon to begin using it. Loopback will walk you through the necessary process to install the ACE (Audio Capture Engine) backend, which is required for the application to function.

Uninstalling Loopback

If you wish to remove Loopback, we'd be grateful if you told us why! You can contact us directly to provide feedback or to get assistance. We're always working to improve our products, so please don't hesitate to tell us what was missing or didn't work for you.

To remove Loopback, first select Uninstall ACE from the Loopback menu. You'll be walked through the process to remove Loopback's ACE (Audio Capture Engine) backend from the system.

Once that process is complete, you can quit Loopback and drag the application to the Trash.

User License

Disclaimer

Loopback (“The Software”) is provided as is. Rogue Amoeba Software (“The Author”) is not responsible for any damage to the user's computer system or data and in no event will The Author, its officers, directors, employees or agents be responsible to the user for any consequential, incidental, or indirect damages (including damages for loss of business profits, business interruption, loss of business information, and the like) arising out of the use or inability to use the The Software, even if The Author has been advised of the possibility of such damages. Because some locations do not allow the exclusion or limitation of liability for consequential or incidental damages, the above limitations may not apply to you. Further, the consumer agrees that using this software in any way illegal, or even for the purposes of assessing its viability for illegal usage, is prohibited.

What that said:

Be safe when you use the software. Be aware that it's simply a tool designed to make your life better. Don't use it to do illegal or evil things. If you do, be ready to take responsibility for your own actions.

Distribution

Unless explicitly stated in writing, Rogue Amoeba Software does not grant permission to sell The Software. Non-profit distribution of The Software in its trial form is generally acceptable, provided that The Software is not modified in any way, the complete works of The Software are included in the distribution package, and Rogue Amoeba has been contacted for confirmation.

What that said:

Don't sell this software. If you wish to distribute it in its trial state, get in touch with us to confirm permission.

Acknowledgements

Portions of this Rogue Amoeba software may utilize the following copyrighted material, the use of which is hereby acknowledged.

Sparkle

Copyright © Andy Matuschak

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.