How do I use Key and Scale with a Switch 3 on the Play Acoustic.
Select 'Setup->Switch-3 6/7->control', and set this to custom. Set switch 1,2 or 3 to set key. When you select the switch that has been set to 'set key' it will change to the set key page. Now use the switches on the Play Acoustic to set your key and scale as desired.
The reason this is useful is because it still leaves the switches free to have loop control when the set key menu is not visible.