W. J. Melvin
W. J. Melvin Musician, producer, sound engineer, composer, chief of MIDI technology @beat_bars

Live looping with MainStage 3 - part 2

Live looping with MainStage 3 - part 2

This is the second part of the article about creating and controlling loops during live performances based on the example of Loopback from MainStage 3. If you want to know how to configure this plugin to be able to record several different sound sources on one loop, see part 1.

Part 2: Assign and Map MIDI events to Loopback functions

In this post I will show you how to configure Loopback to be able to control the following functions: Record / Play / Stop / Clear / Undo / (any other function), using a MIDI controller, as well as how to connect any standard guitar footswitch to become such a controller.

Let’s start with the footswitch. There are a lot of footswitches on the market designed to work with classic guitar amps. Each professional amplifier manufacturer has several of them in their product range. Most of them are standard one- or two-button footswitches, which are fully interchangeable between models from different manufacturers. There are also standard switches, not associated with any particular brand and compatible with most guitar amps.

Marshall foot-switch Boss FS-5L

The only problem is that they are not MIDI switches and cannot be directly connected to the computer.
Fortunately, there are also adapters that enable this, e.g. FS2M, which transforms this analog footswitch into a fully customizable MIDI controller.
We recently released simple, autonomous MIDI Footswitch FS3, which do not require any adapters.

Once you have the MIDI footswitch ready, you can configure the Loopback plugin to react to MIDI messages appropriately.

Open your example Concert which you created in the previous episode, and switch to “Edit” mode.
Edit View

If in the previous section you created a Loopback Channel Strip on the “Concert” level, also now select Concert, not Patch.
Patch List - Concert

The central view of “Assignments & Mappings” is essential, especially the “Assign & Map” button on it, which is grayed out if you do not click on any Assignment. Now when you press the button on the footswitch and you have the “Selection follows incoming MIDI” option selected (by default, the ⚙ icon)
Selection Follows Incoming MIDI

you will see a yellow dot at the beginning of the “Unassigned” line. This means that the MIDI event has been detected, but it is unassigned and unmapped.
Unassigned MIDI

Now add New Assignment
New Assignment

and click on this new row to make the “Assign & Map” button enabled. Click on this button to activate “MIDI Learn” mode (the button becomes red).
Assign and Map - MIDI Learn

Press the button on the footswitch - this way you will assign a MIDI event to this Assignment. Click the red “Assign & Map” button again to deactivate “MIDI Learn” mode.
Assignments and Mappings - Unmapped

You are done with the “Assign” operation, now let’s move on to the “Map” procedure.

In the “Control Inspector” view below the “Assignments & Mappings” view, under the “Unmapped” tab there is a list of possible parameters to be mapped.
Channel Inspector - Unmapped Tab

Click: Loopback ► Loopback ► Non-automatable ► Transport ► Record.

The new Assignment is now fully configured.
New Assignment - Configured

From this moment, each time you press the footswitch button, you will start recording the loop. Open the Loopback plugin and make sure you’ve set up everything correctly.

This one button is not enough to use Loopback live - you still need at least one more button responsible for the “Play/Stop” function. It’s sometimes convenient to have the “Clear” and “Undo” actions under your feet (depending on your needs). To connect 4 buttons, you will need two double footswitches and two adapters.
Proceed in the same way as before, assigning more buttons and mapping them this time to the parameters: Play/Stop, Clear and Undo. Make sure beforehand that each footswitch button has a different MIDI CC# set. In the case of the FS2M adapter, dedicated configuration software is used for this.
FS2M config app
It is also good to stick on some tape on the footswitch with the names of the buttons:
Footswitch Buttons

In part 3 we will talk about configuring the settings of Loopback and controlling it.