Logic Pro - Assign expression command

Context

Like many others who use virtual instruments, especially orchestral sound samplers that reproduce sampled acoustic instruments sounds, the need to control both volume and sound modulation quickly appeared to me as a challenge to achieve maximum realism in sound rendering.

Various solutions are possible:

• Acquire an external MIDI controller module, preferably with sliders (at least two) that must then send the appropriate MIDI signals (cc 11 for expression, cc1 for modulation).
• Use an expression pedal (which will possibly be connected to the MIDI keyboard) and also use the keyboard's modulation wheel.
• Reassign the portamento wheel (Pitchbend) to become an expression controller and keep using the modulation wheel.

External Module

Various MIDI mixer controllers offer the possibility to reassign controller MIDI messages using a dedicated application. Korg Nanokontrol or Icon Pro Audio Platform X+, for instance could be used for this purpose.

Modular controllers have begun to emerge since 2020, and these are generally fully configurable via a dedicated application. Among them, Monogram offers its Creative Console series, and Intech offers its Grid modules.

In any case, unless you already own one of these devices, there will be something to spend, and in some cases the amount could be substantial.

Expression Pedal

Using an expression pedal (such as the Roland EV5) is a less expensive solution and has the benefit of avoiding the need for configuring MIDI sent signals since, as soon as it is connected to the controller keyboard, it will emit the appropriate signal (cc 11).

The simultaneous use of a pedal for expression and the keyboard's modulation wheel requires some training though, and as I am an amateur keyboardist, this is not and ideal solution.

Using the Portamento Wheel

Most controller keyboards have two wheels, one for portamento (Pitchbend), which are side by side. When using banks of orchestral instrument sounds, the portamento is already implemented in the "legato" articulation. Sure the portamento wheel can be used to recreate note glides, but the rendering does not offer the same realism as legato, meaning this wheel can easily be used for something else. The proximity of these two wheels (portamento and modulation) allows the use of this pair in sync, which is much easier than with the pedal-wheel tandem. However, the portamento wheel signal must be modified to be assigned to the expression command (cc 11).

Here, Logic Pro users are privileged, as the software has a layer that allows a lot of flexibility in configuration, especially MIDI signals. Users of earlier versions of Logic (9 and earlier) remember the "Environment" window, which could initially appear a bit daunting and nebulous. Logic version 10 still has this layer, but you need to activate advanced settings to make it appear.

Configuring the Logic Pro Environment

The exercise involves a few steps. However, once the configuration is done, the Logic session can be saved as a template file (File menu, Save as Template). (Note: all the screen pictures below have been taken on a french Canadian computer, but the english commands have a similar display).

1- Activate advanced features in Logic. This can be done through the Settings menu, Advanced.

When the advanced settings window appears, check the Enable Full Features box.

2- To bring up the Environment window, it is imperative to hold down the Option [ALT] button and then under the Windows menu, choose Open MIDI Environment.

Once the Environment window is open, you get something similar to this:

3- To be able to transform a MIDI signal into another MIDI command, you must first create an element called Fader. In the menu of this window, choose New, then Fader, then Automatic.

4- Once the new fader is created, you must indicate to it the type of incoming signal and the desired command parameter for the outgoing signal. This is done by clicking on the word Fader at the bottom of it. In the left panel, you will see the default parameters of the fader. Make sure the parameters are modified as shown in the following image.

5- Well, we have created the module that will transform the signal. Now we need to allow it to transmit the transformed signal to the sequencer. For this, simply create a Sequencer Input module as shown in the following image.

You then need to connect the output of the slider to the input of the sequencer with a virtual cable. Point the mouse at the small output icon in the upper right corner of the Fader and drag the virtual cable created to the left of the Sequencer Input module.

6- The last step is to feed the new Slider with a signal that will come from the external, i.e., your keyboard. You need to create a new Physical Input module as shown in the image below.

To connect the Physical Input to the Fader, proceed in the same way as for the Sequencer Input, i.e., connect the Sum output (which includes all external MIDI inputs detected by Mac OS) to the left side of the Fader.

There you go, Logic is ready to receive an Expression signal via the portamento wheel.