How to change concert pitch frequency in garage band e.g. Tune to 528 hertz instead of 440
I would like to change the tunning from standard concert pitch to another hertz.. this may not be the the same as transposing
You cannot change the reference tune much to allow you to play non standard scales. "A" can be in the range of 410 to 470 Hz.
See this page on tuning: http://help.apple.com/garageband/mac/10.1/#/gbndb40183f2
Reference Tuning field: Drag vertically to set the pitch of the note used as the basis for tuning. The default is for note A at 440 Hz and can be set in a range from 410 to 470 in 0.1 Hz steps.