Thank you for your answer.
Yes, the MIDI synth is plugged into speakers.
And the MIDI Receive on the synth is set to the proper channel.
The Config Test on MIDI & Audio Utility works fine: I've got the sound!
Hence the question about the '09 release :(
I tried to install MIDIo 1.2 as described but I get no sound from my MIDI synth. The connection seems fine since the Audio & MIDI configuration test is ok.
Is MIDIo 1.2 compatible with GarageBand '09 or did Apple change something in the Audio Unit format?
