[adam79]

I have some stuff recorded on external devices, with just a headphone
output, that I want to transfer to my Mac as mp3s. I connect the
headphone jack to the Mac input jack, and open a GarageBand session.
After creating a new "real instrument" track, I start the playback on
the external device, but GarageBand doesn't play the audio through the
speakers; I have the track on record and the dB meters are registering.
The only time it lets me listen to the audio is after I record and
playback the recording track. Is there a way that I can listen to the
audio before and during recording? I have the preferences set to "System
Setting," for the audio output (which is the default setting), and
"Built-In Input" for the audio input.

Is there something that I'm missing, or does GarageBand not have this
feature (it's usually called Rehearsal or Practice mode on other
recording devices/software)?

Thanks,
-Adam