
Set channel strip input format in Logic Pro for Mac
The channel input format determines the mono, stereo, or surround state of the channel strip. The symbol on the button indicates the current state as follows:

Mono: One circle represents a mono input format. The level meter shows a single column.
Stereo: Two interlocked circles represent a stereo input format. The level meter divides into two independent columns when a stereo input format is chosen.
Left: Two circles, with the left one filled, indicate a left channel input format. Only the left channel of a stereo audio file is played back. The level meter shows a single column.
Right: Two circles, with the right one filled, indicate a right channel input format. Only the right channel of a stereo audio file is played back. The level meter shows a single column.
Surround: Five circles indicate the surround channel input format. The level meter divides into multiple linked columns (the number matches the project surround format) when the surround input format is chosen.