Introduction to MIDI Specification

Overview

• MIDI: Acronym for Musical Instrument Digital Interface.
  • A set of standard communication specifications for transmitting musical information between electronic instruments and computers.
  • Introduced in 1983 by Dave Smith of Sequential Circuits.
  • Based on Roland DCB standard.
  • Purpose: Enable different instruments and devices to communicate using a universal standard.

Evolution and Impact

• Before MIDI, manufacturers had proprietary control schemes (e.g., Moog, Korg, Yamaha) that weren’t compatible with each other.
• MIDI allowed for cross-manufacturer communication, facilitating easier integration and compatibility across devices.
• Adopted quickly across the industry; became a universal standard.

MIDI Management Organizations

• MIDI Manufacturers Association (MMA):

  • Defines MIDI specifications and standards.
  • Coordinates with manufacturers and users.
  • Geographical responsibility: Americas and Europe.

• Japanese MIDI Standards Committee (JMSC):

  • Same responsibilities as MMA.
  • Geographical responsibility: Asia and Pacific Rim regions.

Key MIDI Manufacturers

• Roland

  • Parent of Boss, known for guitar pedals, drum machines.

• Korg

  • Manages Marshall and Vox, known for amps, effects.

• Yamaha

  • Broad range of products including musical instruments, audio equipment, and even non-musical products.

MIDI Basics

• Communication Language: Performance data only, no audio.

  • Captures actions like note strikes, velocities, wheel movements.
  • Allows for easy sound changes and modifications (e.g., transposition, quantization).

• Transmitter and Receiver:

  • Transmitters send MIDI data (usually devices with keys).
  • Receivers respond to MIDI data (e.g., rack-mount devices).

MIDI Cables

• Five-pin DIN Cable

  • Uses pins 2, 4, and 5.
  • Pin 5: Data, Pin 2: Ground, Pin 4: +5V Bias Voltage.
  • Safe from accidental misuse due to unique pin configuration.

• Maximum Cable Length: 50 feet.

• Channels:

  • Supports 16 independent channels, akin to mixer channels.
  • All data travels serially through one pin.

Data Transmission

• Speed: 31.25 kilobaud (31,250 bits per second).
  • Handles typical MIDI messages (16 to 24 bits per message).
  • Fast enough to manage multiple notes and channels efficiently.

Conclusion

MIDI remains a crucial technology for musical instrument communication, ensuring compatibility and creativity across diverse electronic music equipment. Its standardized nature and management through MMA and JMSC help in sustaining its relevance and adaptability over the years.