How do you route the line-in audio to line-out on Mac Pro (10.6.8)?

Question

New to Mac. Seems like it should be a straight forward deal, but it's not obvious how to make this happen.  I can tell the audio is coming in, as the input levels are reflected under System Pref's.  But I can't hear the audio on the line-out speakers and there doesn't seem to be an option to explicity route the audio.  Probablly missing something simple.  Any help would be appreciated.

Answer 1

You can do this without buying or using 3rd party s/w. Use GarageBand this way:
1. New, Empty Project
2. On the next screen, choose:
     a. Audio, Line In
     b. Input 1+2
     c. Check the "I want to hear my instrument as I play and record" option
     d. "My instrument is connected with:" - Built-in Input
     e. "I hear sound from;" - Built-in Output
     f. Click "Create"
3. You should immediately hear sound; you don't have to record anything.
4. If you don't see green bars on both the Audio 1 track and the master volume (top right), something is either wrong with your input or the steps didn't work for you. To redo the steps, choose "Track, Delete Track" from the menu and try again.
IMPORTANT: Make sure that all of the needed volume controls are up high enough to hear something:
1. Audio 1 volume and Master Volume sliders in GarageBand
2. Volume slider on Apple main menu, speaker icon not muted
3. Volume on input device (e.g. iPhone)
See how you go
P.S. I do it on a mac mini but it shouldn't be any different
Message was edited by: SilverSkyRat