I got Rock Band for XBox 360 last night, and started playing it tonight. Its a lot of fun playing the drum set, but I realized almost immediately that it seems to be missing a ‘freestyle mode’ that would let you just wail.

The drum controller is a wired USB device, so I figured I would try getting it to work on my Mac with Garage Band. Turned out to be pretty easy. To get it working you’ll need:

• A Mac
• Garage Band
• Rock Band for XBox 360
• XBox 360 Controller Driver - Open Source & GPL
• Gamepad Companion (makes it so you can map the keys on your controllers) - Proprietary / Shareware

First step is to leave your drum set unplugged from your Mac (if you plugged it in you’ll realize it is recognized as a Harmonix Drum Kit for Xbox 360). Install the Xbox 360 Controller Driver and Gamepad Companion. The 360 Controller Driver installer will say you need to reboot–but it worked for me without rebooting.

If you launch System Preferences you’ll notice a few new panes at the bottom.

Click on XBox 360 Controllers first. Plug in your drum kit, and it should locate the controller immediately. Go ahead and belt out a few hits to make sure that the buttons are lighting up as they should.

Once satisified, go ahead and click “Show All” to get back to System Preferences. The controller is working and recognized, but we need to map the buttons to keys that Garage Band can recognize. To do that we’re going to click on Gamepad Companion.

The driver maps the buttons like so:

• Button 1 = Green
• Button 2 = Red
• Button 3 = Blue
• Button 4 = Yellow
• Button 5 = Kick/Pedal

When we set up the keyboard interface in Garage Band later, certain keys will activate certain instruments. Here is a good key-mapping setup that works for most of the drum kits in Garage Band that features a bass/kick drum, a snare, two toms and a cymbal.

• Button 1 Map to U
• Button 2 Map to S
• Button 3 Map to J
• Button 4 Map to F
• Button 5 Map to A

There are tons of other instruments and configurations you can use, but this will get you started. Once you’re done mapping the buttons, go ahead and click “Start” to enable Gamepad Companion.

Just to make sure everything is working, I’d recommend opening up TextEdit or some other editor and wail a bit on the drums, to make sure that it is mapping the keys properly. If it is, you should see a bunch of letters typing across the screen. The repeat rate seems like it would be a problem in Garage Band, but it works fine the way it is.

Now it is time to launch Garage Band. Start a new song, which will have a default instrument of “Grand Piano”. Double-click “Grand Piano” to show the Information/Instrument drawer. Browse to “Drum Kit” and then select “Rock Kit”.

We now have to configure the keyboard. Hit Command-K or Window->Keyboard to bring up the keyboard interface. Basically the Mac keyboard is just to small for all the musician’s keys. So we need to select the C1 octave range either by dragging the blue selected keys, or hitting the plus/minus octive buttons (either on-screen or by hitting Z / X). Once you have C1 selected, you’re ready to rock!

Added note: It is possible to get the Rock Band Drums working with software on the Windows Platform as well, and apparently the PS3 controller works in a similar fashion.