Modulation Monday – Getting Started

Published by john worthington on

Some people say samples aren’t expressive. I find that’s usually because they haven’t gotten very deep into modulation. Modulation lets you affect the properties of a sound during playback. Perfect for adding expression and life to your performance. The Jambé app features an expressive set of modulation options and to help you get the most out of it, I’m starting a new series here – Modulation Monday.

If you haven’t already enabled Edit Mode in the Jambe app, it’s time. Open up the settings menu and make sure “Edit Mode” is checked.

If it is, you should see a control at the top of your screen with these options.

The Modulation Subview of the Instrument Editor shows the Mod Path editor for the selected Instrument. There are equivalent Mod Path editors for the Kit and each FX preset. Each of the three different Mod Path “contexts” are separate and distinct with their own modulation sources and destinations available. We’ll begin by focusing on the Instrument Mod Path editor.

Each Instrument has 16 different modulation paths (“Mod Paths”) available, shown in a table on the left side of the screen. Selecting a Mod Path in the table displays the Path’s parameters for editing on the right side of the screen.  Each Mod Path is assigned one of three colors, indicated by a colored circle next to its name in the table.  Green means that the Mod Path is valid and actively being used.  Yellow means that the Mod Path has been put into Bypass mode and is not being actively used, and Red means that the Mod Path is not valid for some reason (it may not have one or more parameters selected, for example).

A Mod Path consists of three components – a source, a via and a destination.  All three need to have a valid value chosen in order for the entire Mod Path to be valid.  Sometimes, certain choices can be invalid, and will be marked in red to indicate that.  For example, an LFO cannot modulate its own speed.  Having source Tracker and a via is optional, but a source and destination are required.

The Bypass Button at the top of the Mod Path Editor allows the Mod Path to be temporarily disabled without having to change any of its parameters.  When bypassed, the Mod Path shows up in Yellow in the table, and does not have any effect on the audio output.

The Gated button, when on, means that the Mod Path is only evaluated while the Instrument’s gate is on.  A gate is a term from keyboard synthesizer terminology.  On a keyboard synthesizer, the gate generally referred to the key while it was pressed.  For example, when a key was pressed, the gate would be ON, and the envelopes would only enter release mode when the key was lifted and the gate would turn off.

In Jambé, the gate refers to the time when there is pressure on the pad after a note has been triggered. If the pressure on the pad is released, the gate would turn off. This is most commonly used to prevent modulation from happening as a note trails off. We’ll cover this in more detail later in the series.

The Mod Source section allows the selection of the Modulation Source with a hierarchical popup menu.  It also allows the optional choice of a Tracker, which can map the response of the source via a mapping (or “tracking”) curve that is user editable.

When the Mod Path is valid and active, the effective value of the Mod Source is displayed in the Value field as a changing bar graph.  The sense of the Mod Source can be inverted and the overall polarity (range of values) can be selectable.  Negative polarity means that the range of values of the Mod Source goes between -1.0 and 0.  +/- (bipolar) polarity means that the range goes between -1.0 and +1.0. Positive polarity means that the range goes between 0 and +1.0.  And -> (pass-through) means that the polarity used is the native polarity of the source, and it is not transformed into any other range. 

There are Edit buttons available for both the Mod Source and the Tracker.  For the Mod Source, the Mod Paths table is replaced by an editor for the specific type of Modulator that is chosen.  For example, if the Mod Source was Instrument LFO 1, an LFO editor dialog would appear.  That editor can be put away by either tapping the “X” closing icon that it presents, or by tapping the Edit button again, which has changed to say “Close”.  The Edit button for the Tracker similarly brings up a Tracker curve editing dialog.

The Via group has a popup menu selector for the via, and an Edit button for it that functions the same way the Mod Source Edit button does.  A via is a separate Modulation Source that modulates the value of the chosen Mod Source.  For example, you may have a Mod Path set up to have an LFO modulate the Pitch of an Instrument.  You could set up a via to modulate the amount of pitch modulation occurring.  If the via was Pad Pressure, then you could have the pressure on a given Pad control the amount of pitch modulation occurring.  The via parameter is optional, and can be None.

The Destination grouping view allows the selection of the Modulation destination.  It also shows its current value when active, and the user selects the maximum amount of that modulation for this Mod Path.  For example, if Instrument Pitch is being modulated, and the Max Modulation is set to 12 semitones, then the amount of pitch modulation that this Mod Path can produce is between -12 and +12 semitones (-1 to +1 octave), depending on the polarity of the Mod Source and any Via being used.

Looking at the Mod Paths from the included pvcWhack kit, you’ll see that there are two active Mod Paths. “Note On Pad Pressure” is an important and frequently used modulation source. Its value is the pressure on that pad at the start of a the note. In the first Mod Path, we’re using its value to select the sample to be played. The result is similar to velocity switching on a MIDI sampler. There are multiple samples in the kit that play back at different modulation levels. In this case the modulation is pressure.

The second Mod Path uses “Note On Pad Pressure” to modulate the “Trim.” The “Trim” modulation destination controls the volume of the Instrument after all of its voice processing but before the audio gets sent to the main output and FX processors. This Mod Path makes hard hits louder than soft hits.

As an exercise before next week, try modifying Mod Path 2 to have “Note On Pad Pressure” modulate “Pitch.”

The Jambé app has over 45 modulation sources including your iOS device’s accelerometer, gyroscope, proximity sensor, magnetometer, and altimeter. There are over 175 modulation destinations. There’s a lot to explore.