MIDI Channels and Ports
Sixteen channels make one port, and track count is never the same thing as channel count.
Related
A channel is the address inside a message, and a port is the container for channels. Both can be counted, yet they are often confused.
The problem
With many parts, sixteen channels run out. Two tracks aimed at one channel mean one fader moves the other, while changing ports is expected to separate channels automatically.
Protocol or message
A port holds 16 channels, numbered 0 to 15. GM fixes channel 10 to drums. A port can be a DIN socket, a USB connection or a virtual port, and each counts separately, so the same channel number can appear on two ports. Omni mode receives every channel. A track is an organising unit in a file, a channel is an address in a message, and the two need not match.
Settings and practice
Give each part its own channel and leave 10 for drums. Label ports in the project when more than one is in use. Virtual loopbacks connect two programs. Avoid two tracks sharing a channel and register. When sixteen channels run out, add a port instead of sharing.
What to listen for
When two tracks share a channel, one track's CC7 changes the other's level. A drum part sent to channel 1 turns into piano keys.
Common misunderstandings
Track count is not channel count. Channel 10 is not the tenth track. USB does not mean unlimited channels.
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 规范的通道消息与端口概念，依 MMA 公开规范核查，未抄文本
- GM 对第 10 通道的鼓组约定，依通用 MIDI 规范核查，未抄文本
Used for fact-checking only; all prose is original.