Official MIDI Specifications


The following changes/additions became part of the MIDI 1.0 Specification after the "96.1" publication and should be consulted to have a current understanding of MIDI technology.
With the approval of CA-025 ("Master Fine/Coarse Tuning") there arises a naming conflict with existing Registered Parameter Numbers (RPNs) in the MIDI 1.0 Detailed Specification called Master Tuning. The original message is by definition Channel- based, which supports renaming those messages "Channel Fine Tuning" and "Channel Coarse Tuning" under the heading of Channel Tuning.
This CA adds an Extended Dump Header, capable of handling sample object sizes up to 32 GB (Gigabytes) with greater precision in calling out the sample rate; a new Extended Loop Point message for longer loops; and a Sample Name Transmission / Request pair, all implemented under the Sample Dump Extensions command tree.
MIDI Tuning Updated Specification.pdf

incorporating the following:
  • MIDI Tuning Bank/Dump Extensions (CA-020)
  • MIDI Tuning Scale/Octave Extensions (CA-021/RP-020)
  • Defaults for Scale/Octave Tuning (RP-020)
The MIDI Tuning specification allows the sharing of "microtunings" (user-defined scales other than 12-tone equal temperament) among instruments, and the switching of these tunings during real-time performance.

The MIDI Tuning messages include:

• Bulk Tuning Dump Request (non-real-time)
• Bulk Tuning Dump (non-real-time)
• Single-note Tuning Change (real-time)

Scale/Octave Tuning is micro-tuning that is automatically repeated in every octave by calibrating a single octave of notes in small fractions of an equal-tempered half-step. The original MIDI tuning dump message had to define a frequency to each of 128 keys. This proposal defines an easier micro tuning that sets offsets from an equal-tempered half-step by the cent.
ca22 Controller Destination SysEx Message.pdf
This proposal enables selecting the destination for Control Change messages, plus Channel Pressure and Polyphonic Key Pressure, using Universal Real Time System Exclusive messages. When coupled with specific recommended practices for response to these controllers, these messages will provide common controller response among a variety of playback devices. See General MIDI 2 Recommended Practice for examples of how the response can be standardized.
ca23 Key-based Instrument Controller SysEx Message.pdf
The Key-Based Instrument Controller message is intended to be a standard method of providing individual key-based instruments with the same performance control that is available for Channel-based instruments. Specific responses to this message may be defined in a separate recommended practice, such as General MIDI 2.
ca24 Global Parameter Control SysEx Message.pdf
This proposal allows the editing of global parameters in a device using Universal Real-Time System Exclusive messages. These global parameters may include effects parameters, system control parameters, or other non-channel-specific parameters. Because there may be more than one instance of an object containing global parameters in the same device, and these multiple instances may have similar parameters or even contain additional objects in an object hierarchy, an optional mechanism is provided for uniquely identifying the "slot" within the object hierarchy containing the global parameters.

When coupled with specific recommended practices for parameters and values, these messages will provide common parameter editing among a variety of playback devices.
ca25 Master Fine & Coarse Tuning SysEx Message.pdf
These two new Universal Real Time SysEx messages are additional Device Control messages which control the overall tuning of a device. The “Master Fine Tuning” and “Master Coarse Tuning” messages are intended to produce the same effect as the pitch shift control on a tape recorder.
ca26 RPN05 Modulation Depth Range.pdf
This proposal defines Registered Parameter Number (RPN) #05 as Modulation Depth Range to be used to scale the effective range of Control Change 1 (Modulation Wheel). The correlation between Modulation Depth Range values and modulation depth is defined by individual manufacturers or MMA/AMEI recommended practices.
(CA-033) MIDI 1.0 Electrical Specification Update [2014]

The MIDI 1.0 Specification includes an Electrical Specification which uses a 5-Pin DIN connector and 5 Volt electronics as was common at that time. The Specification was updated in 2014 to reflect current design requirements such as 3.3 Volt circuitry and reduced RF interference.

Electrical Specification Update 1.1 [2014]
This updates the MIDI 1.0 Electrical Specification to include 3.3-volt signaling. This update also adds optional ferrite bead RF filters to the signal pins, and optional grounding provisions for the grounding shield connectors on the MIDI jacks.

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