MIDI Pitch Bend Depth: How Bend Limits Work
MIDI pitch bend depth defines the maximum musical interval an instrument shifts when its pitch bend controller is pushed to its extreme limits. While standard MIDI pitch bend messages only tell a synthesizer where the physical wheel or lever is positioned, they do not dictate how far the pitch should actually shift. To change this limit, an instrument receives dedicated control messages—most commonly through Registered Parameter Numbers (RPN)—or relies on manual patch configurations.
What is the MIDI Pitch Bend Depth Parameter?
Pitch bend messages transmit a 14-bit value ranging from 0 to 16,383, where 8,192 represents center or no pitch shift. This message communicates only the position of the controller, not the pitch interval.
The pitch bend depth parameter (also called pitch bend sensitivity or range) determines what that 14-bit range translates to musically. By default, most General MIDI synthesizers set this range to two semitones (a whole step) up and down. If a player sets the depth to 12 semitones, moving the pitch wheel to its highest point will shift the pitch up by a full octave instead of a whole step.
How Instruments Receive Changes to the Bend Limit
Because standard pitch bend messages do not contain range information, MIDI utilizes Registered Parameter Numbers (RPNs) to adjust this setting dynamically. Pitch Bend Sensitivity is standardized as RPN 0.
To change the bend limit via MIDI, a controller or DAW transmits a specific sequence of Control Change (CC) messages:
Select the Parameter (RPN MSB and LSB):
- The sender transmits CC 101 (RPN MSB) with a value
of
0. - The sender transmits CC 100 (RPN LSB) with a value
of
0. - This combination signals to the receiving synthesizer that subsequent data changes apply specifically to the Pitch Bend Sensitivity parameter.
- The sender transmits CC 101 (RPN MSB) with a value
of
Set the Value (Data Entry):
- The sender transmits CC 6 (Data Entry MSB) with a
value representing the desired range in semitones (e.g., a value of
2sets a 2-semitone limit; a value of12sets a 12-semitone limit). - Optionally, the sender can transmit CC 38 (Data Entry LSB) to adjust the limit in fine increments (cents), where each step represents approximately 0.78 cents.
- The sender transmits CC 6 (Data Entry MSB) with a
value representing the desired range in semitones (e.g., a value of
Reset the Parameter (Null RPN):
- To prevent accidental modifications from future data entry messages,
the sender typically transmits CC 101 with a value of
127and CC 100 with a value of127. This deselects the active parameter.
- To prevent accidental modifications from future data entry messages,
the sender typically transmits CC 101 with a value of
Alternative Configuration Methods
While RPN 0 is the universal standard for real-time automation, instruments can also adjust their bend depth through other means:
- Software and Patch Settings: Most modern software instruments (VSTs) allow users to set the pitch bend range directly within the instrument's graphical user interface, storing the value on a per-preset basis.
- System Exclusive (SysEx) Messages: Certain vintage or proprietary hardware synthesizers utilize manufacturer-specific SysEx strings to alter pitch bend depth when RPN implementation is absent or overridden by global settings.