Asking QuickTime Player 7 to play MIDI files through GarageBand By just launching a MIDI file it will play by default using QuickTime Player 7, but the volume is rather low and the sound is far from polished.

How can I ask QuickTime player 7 (or any other application) to send the MIDI stream to GarageBand.

I have already done it from EarMaster to GarageBand and the difference is spectacular, but no option in QuickTime Player lets me select the IAC Driver.

I am hardly attached to QuickTime Player. If GarageBand will play MIDI files, please mention how.
If you have a blank Garage Band song open and you drag a Midi file in and drop it onto the timeline, it will import the tracks.