Using Loopback to send audio from one application to another

Using Loopback to send audio from one application to another

MacOS has a nice built-in feature called IAC (Inter-app Communication) that allows you to connect MIDI applications together and communicate with each other. (There’s nothing built into Windows but there are third-party applications like virtualMIDI that do the same kind of thing.)

However, there is no out-of-the-box mechanism to allow audio to be shared like this. So what do you do if you have a great audio application that you’d like to use with Gig Performer but that application doesn’t exist in a plugin format that can be loaded directly into Gig Performer?

Turns out there are several solutions out there. There are two free tools available, SoundFlower (macOS only), Jack which is available for both Mac and Windows and VB-Cable (Windows only). NB: SoundFlower has been around for many years, developed originally by Cycling74 , but it’s not really maintained any more so you’re basically on your own. As for Jack, while it is supposedly very flexible, I have struggled with it every time I’ve tried to use it in the past.

However, last year, much to my delight, Rogue Amoeba, makers of the brilliant Audio Hijack application (which is worth checking out if you need to capture system audio for other purposes, nothing to do with Gig Performer), released an application called Loopback (Mac only) which makes it really easy to create virtual audio “cables” to let you connect the output of one audio application to the input of another.

Even better, you can create a virtual audio interface and by using the aggregate mechanism built into macOS you can create a “new” audio interface that consists of your existing physical audio interface and some extra virtual channels that just appear as extra audio ports.

For Gig Performer users, there are at least two very interesting and powerful uses for Loopback.

  1. You can leverage audio functionality available in Max, Bidule or even such esoteric programs such as SuperCollider and feed audio from them (or to them) to (or from) Gig Performer.
  2. You can leverage the multi-instance feature of Gig Performer to run a looper (say) continuously in a secondary Gig Performer instance and feed its audio output back to your main Gig Performer instance where you can use different rackspaces to perform different audio processing of the looper output.

I have been using Loopback on tour for about 6 months to feed audio from Max back into Gig Performer. To be honest, I’d almost forgotten it was part of my setup and I just never have to interact with it. From my perspective, the best thing about Loopback is that you can (really easily) set it, forget it and it just works. As far as I’m concerned, that’s worth the price of admission!

Loopback is not free but Rogue Amoeba is offering a $25 discount for Loopback for customers who have purchased the Mac version of Gig Performer. Those of you who have been following our blogs will be aware that we do not receive any portion of such sales so that you can be sure our recommendations are completely unbiased. More on our policy here.

Note: if you are on Windows, there is an application called LoopBeAudio available that appears to have similar functionality. However, none of us at Deskew Technologies have tried it so I am unable to say anything about it (either good or bad) so I’m just bringing it to your attention in case it is of interest to you.


Related topics:
How to set up live streaming using OBS, Gig Performer and JACK Router
How to use a single client ASIO driver with multiple applications on windows

Scaling Curves

Scaling curves allow you to control the shape of the output of a widget or convert an incoming note velocity to a new velocity. Various predefined curves are available and they can be tweaked as necessary. You can also just draw your own curve as well to achieve the effect you require.


MIDI File Player Plugin

You can load up to 128 MIDI song files in a single plugin instance. Switch from one song to another, mute tracks and/or change their channel numbers. Tempo can be controlled by individual songs or you can use the global tempo and tap tempo to control the BPM interactively.


Favorites and Presets

Create a sound by placing and interconnecting your desired plugins, such as a synth, some effects and perhaps a mixer. Select them all and then save the selection as a named favorite. The favorite will subsequently show up in all plugin insert menus, making it easy for you to recreate that configuration whenever you need it again. This feature is also very powerful for creating your needed sounds on your studio computer and then transferring them to your touring laptop.


Probabilistic Sound Designer

Parameters you select in an open plugin are captured into the Probabilistic Sound Designer dialog window. When you click Randomize, you're only adjusting those selected parameters. Each entry in the PSD dialog has a curve but unlike widgets where the curve controls scaling, in the PSD the curves are used to define the probability of particular values being selected. Make sure the filter cutoff never gets too slow so as to block all sound. Perhaps adjust the max range of the VCA attack parameter so that the sound doesn't have too much delay. Constrain the octave ranges of the oscillators, perhaps ensuring that 1/3rd of the time we select 8' and 2/3rds of the time we select 4'. The possibilities are endless.


More Widgets

Numerous new widgets are included in Gig Performer - a new sustain pedal, plastic knobs, drum pads and more colored sliders. Shapes can be colored with different borders and fill colors and morphed from rectangular to circular. Your creativity is now the limit to creating fabulous front panels in Gig Performer.


MIDI Message Helper

Select MIDI devices by name. Choose the MIDI message type and adjust the appropriate parameters for the specific type



Layout management

Gig Performer supports arbitrary resizing. Layout your widgets the way you want - resize the main window and the widgets will grow or shrink as necessary to maintain the same interrelationships. No matter what size screen you have, your front panels will still be neat and usable.


Undo Support

If you move your widgets around and/or resize them, or even delete them by mistake, the Undo facility will correct your mistake. Minor moves to a widget by mistake will no longer spoil your design


Plugin Channel Count

Some plugins support a large number of outputs and they depend on the traditional channel strip to control how many ports should be available.   When you only need a stereo pair, it is convenient not to have a large horizontal block. In Gig Performer, the number of available ports  is controlled by the channel count override, which can be applied to individual plugins and will be remembered when the gigfile is reloaded or if the plugin is saved as a favorite.


Input muting and output fading

Rather than a single audio length tail, Gig Performer 4 gives you the ability to control input muting and output fading separately. Input muting controls how much time it takes for audio input to be silenced when you leave the rackspace. Output fading controls how much time will be taken for audio to fade out when you leave the rackspace.


Faster Plugin Finder

Instead of searching through menus of perhaps hundreds of plugins (you know who you are!), the Quick Plugin Finder makes it easy to find the plugin you need by simply typing partial strings. For example, as shown here, to find the Modartt Pianoteq 7 plugins, it's enough to type pia mod 7 (in any order, by the way)  to restrict the list of available plugins to those matching your query. The Quick Plugin Finder also knows about manufacturers, presets and favorites.



Touch Friendly Input

Any entry field can be changed by either dragging your mouse (or finger) up or down, or by using the large popup touchpad where you can just tap on the squares to enter a value. The large popup keypad also does validation so you can't enter an invalid value. You can also just tap the BPM field to pop up a larger view where you can quickly change tempo, tranpose, trigger Tap Tempo and enable Ableton Link, the last allowing you to synchronize Gig Performer with any other application that also supports Ableton Link.


New Tuner Display

The tuner view makes it easy for guitarists to quickly check and adjust their tuning. You can toggle into the tuner view from any other view and toggle right back as soon as you're done. All output will be silenced automatically while you're in tuning mode. You can adjust the concert reference pitch from its default of 440 Hz to suit your own needs. The tuner view fills the entire screen so you can easily see it from a distance.