While a lot of people upon first spying an iPad thought, “This will be perfect for Angry Birds!” musicians instead responded, “There’s my next portable studio.” The problem was that while the iPad, with its large work surface and highly portable form, seemed like an ideal musical companion, there were no ideal ways to attach musical instruments to it other than tethering one device at a time via Apple's iPad Camera Connection Kit. Alesis has capably addressed this issue with its $399 iO Dock Pro Audio Dock for iPad. Available everywhere for a street price of $199, the iOS Dock is a versatile piece of gear that many musicians will like.
The iO Dock is made of plastic, meaning it’s reasonably lightweight but could be subject to damage if you’re not careful. It includes a multitude of ports for a docked iPad or iPad 2. (Early iOS Docks shipped without the plastic insert that allows the iPad 2 to fit properly in the dock. The unit I received included this insert.) These ports include MIDI In and Out (the traditional 5-pin connectors), USB MIDI, headphone, stereo main outputs (for connecting to an amplifier, mixing board, or powered speakers), two guitar/XLR microphone inputs, a composite video out, and a footswitch port. It supports both line-level and guitar input and offers phantom power for those microphones that require power to work. It also powers an iPad plugged into it (provided the iOS Dock is connected to power and switched on).
Which of the dock’s ports function depends entirely on the app you’re running on the iPad. The iPad supports CoreMIDI and as long as the app you’re using does as well, you should be able to play the instruments available within that app with a MIDI keyboard. Apple’s GarageBand for iPad app, for example, accepts MIDI input. It doesn’t, however, support MIDI output so you can’t then play sounds on your MIDI synthesizer using the iOS Dock’s MIDI out connection. Similarly, GarageBand doesn’t support an external footswitch so that port likewise does you no good.
I connected a microphone requiring phantom power, MIDI keyboard, and guitar to the iO Dock, inserted my iPad 2, and fired up GarageBand for the iPad. I was able to use each device, depending on which instrument I chose in the app. For instance, when I chose the Smart Guitar, Keyboard, or Drums I was able to trigger that instrument’s sounds with my MIDI keyboard. My keyboard’s Pitch and Modulation wheels worked as well, as did the sustain pedal and a volume slider. When I chose the Guitar Amp I could monitor and record the guitar as well as apply GarageBand’s amps and effects to it. And when I chose Audio Recorder I could record my microphone.
When recording two devices that are plugged into the XLR/guitar jacks in GarageBand—in this case the guitar and microphone—the trick to sending the right device to the correct instrument is tapping the Monitor icon within the app (the one that looks like a guitar connector) and choosing the channel the device is plugged into. For example, if you have your guitar plugged into the dock’s left input, that’s the one you’d choose in the app.
Macworld’s buying advice
The iO Dock provides a great way to attach a variety of musical devices to an iPad, turning that iPad into a competent musical companion. All we need now are more great music apps to take advantage of this slick avenue to the iPad’s musical powers.