When Electronic Musician magazine asked me to write a tips article about the Frontier Design AlphaTrack, I was intrigued by the challenge. What could I possibly say about a $200 USB volume slider? I composed the first line in my head before the box even arrived: A controller with just one fader? Isn’t that like a piano with just one key?
The Frontier AlphaTrack adds a motorized fader, transport controls, knobs, buttons, and a ribbon controller to your computer. It’s powered by USB.
The magazine cut that line, but I quickly answered my own question by plugging the AlphaTrack in to my Mac and sniffing its output with Snoize MIDI Monitor. Lots of possibilities there!
I discovered that each of the buttons sent out a distinct MIDI note, whereas the knobs sent out a burst of Continuous Controller messages and the fader sent Pitch-Bend.
In programs that support MIDI learn (i.e., mapping a MIDI event to a command like return to zero or solo track 3), you can quickly set up memorable AlphaTrack keystrokes to control their functions remotely. For example, the computer’s spacebar controls Start/Pause in most music programs, but other common functions like Record and Fast Forward are assigned to different QWERTY keys in each program, so it’s nice to standardize them in a dedicated remote control.
Frontier provides enhanced maps for several popular music programs, but the program I use the most, BIAS Peak, doesn’t even support MIDI control. Just as I was bemoaning that shortcoming, I discovered another free Mac program called (oddly) midiStroke. Its 70KB of code translates incoming MIDI commands to Mac keystrokes. By mapping the AlphaTrack’s Play button (MIDI note 94) to the Mac spacebar, I suddenly had remote control of Peak, QuickTime Player, and iTunes.
Spinning an AlphaTrack knob while watching MIDI Monitor, I noticed that it sent out CC 18 messages—a stream of 1s when turned clockwise and 65s when turned counterclockwise. Using midiStroke, I mapped those to Command-UpArrow and Command-DownArrow, and now I had a real volume knob for iTunes. For the ultimate in remote laziness, I assigned an AlphaTrack button to trigger my iTunes fadeout AppleScript.