MIDI versus Audio
MIDI stores actions and audio stores waveforms, so what can still be changed afterwards differs completely.
Related
Recorded audio is a waveform, so changing one note means re-recording or cutting it apart. MIDI stores actions, and pitch, tempo or instrument changes are only edits to numbers.
The problem
Confusing the two sends you to the wrong track. Intonation that audio cannot fix is one pitch bend away on a MIDI track, while a real room cannot be produced by MIDI at all. Sessions hold both.
Protocol or message
Audio stores amplitude at the sample rate, so 44.1 kHz means 44,100 samples per second, each rounded to a bit depth. MIDI carries at most 3,125 bytes per second, and a note message takes three bytes. Audio length comes from the sample count; MIDI length from tempo and bars. Audio pitch is fixed in the waveform, while a MIDI pitch is only a key number.
Settings and practice
Record MIDI and render it for performance detail with free timbre. Record audio for a real microphone, room and noise. Align both from one start point and compensate for render delay. By the mix, MIDI becomes audio or is synthesised by the DAW.
What to listen for
Audio stretched in tempo shifts pitch or leaves artefacts; MIDI changes tempo without touching timbre. Swapping a melody's sound takes an instant in MIDI and a new take in audio. Repeated audio phrases differ slightly, while repeated MIDI phrases are identical.
Common misunderstandings
MIDI is not compressed audio. A MIDI track makes sound, but the sound comes from a source. Audio pitch can be edited, at a different cost. Both kinds of track feed one bus.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- MIDI 1.0 的传输速率与消息长度，依 MMA 公开规范核查，未抄文本
- 数字音频采样率与量化的定义，依通行数字音频教材核查，未抄文本
Used for fact-checking only; all prose is original.