Table 3 – Frequencies in hertz (Hz) and frequency levels in semitones counted (sc) up from C0 for the usual equal-tempered scale. Subscripts by octaves above C0. C0 approximately equals 16.352 Hz so that A4 = 440 Hz exactly
Table 2 — Interval comparisons in different mathematical tuning systems
Musical Instrument Digital Interface
12.31 MIDI; Musical Instrument Digital Interface. A widely accepted communications protocol enabling music synthesizers, computers, and related equipment to communicate, control, and synchronize with each other.
MIDI
12.31 MIDI; Musical Instrument Digital Interface. A widely accepted communications protocol enabling music synthesizers, computers, and related equipment to communicate, control, and synchronize with each other.
standard musical pitch
12.30 standard tuning frequency; standard musical pitch. Frequency for the note A4, 440 Hz. Annotation See Table 3.