The iOS 4.2 update to the iPad included a full range of MIDI functionality, which opened the door for a whole host of cool music apps for the iPad. In addition to playing virtual instruments and recording in a multi-track studio environment, you can use your iPad to do everything from tune your instrument to keeping up with your library of sheet music.
Easily the most popular music app, GarageBand packs in quite a bit of functionality for a relatively low price. The recording studio, ability to plug in a MIDI controller and dozens of different virtual instruments will appeal to musicians, and the inclusion of 'smart' instruments make GarageBand a great app for the want-to-be musician. Another great feature is the ability to play along with friends over Bluetooth or Wi-Fi and record them all onto the same iPad.
Music Studio is for those that like the concept of GarageBand but feel constrained by its limitations. The basic concept is the same: provide virtual instruments in a studio setting that allows for the creation of music. But Music Studio adds more sequencer features, including the ability to edit tracks, add effects and draw in additional notes with the digital pencil tool. Music Studio also has a comprehensive range of downloadable instruments, so you can expand your sounds as needed.
Want to ditch the virtual instruments but keep the recording capability? No need to go with a more expensive option. Hokusai Audio Editor allows you to record multiple tracks, copy and paste sections of the track and apply different filters and effects to your tracks. Best of all, the base package is free, with in-app purchases allowing you to expand the capabilities of the app with new tools like grain synthesis, time-stretching, reverb, modulation, etc.
ThumbJam is a virtual instrument designed specifically for the iPad, iPhone and iPod Touch. Rather than provide an on-screen keyboard linked to instrument sounds, ThumbJam turns your device into an instrument. By picking out a key and scale, you can use your thumb to move up and down the notes and wave the device to provide different effects such as pitch bend. This makes it a unique and intuitive way to 'play' your iPad.
One area where the iPad really excels is as a drum machine. While playing a virtual piano or guitar on the touch screen can be a little awkward, with the lack of tactile sensation leading to missed notes, the touch screen provides a fairly good imitation of drum pads. You might not get the touch sensitivity or advanced features of real drum pads, but for those wishing to tap out a beat, DM1 is the next best thing and far cheaper than a real drum machine. Along with drum pads, DM1 includes a step sequencer, a mixer and a song composer.
Not sure you want to spend the money? Rhythm Pad is a good alternative to DM1 and has a free version you can use to check it out.
Fans of the synthesizer will love Animoog, a polyphonic synthesizer designed specifically for the iPad. Animoog includes waveforms from classic Moog oscillators and allows users to fully explore the space of those sounds. At $29.99, it's easily the most expensive app on this list, but for those wanting a true synth experience out of their iPad, Animoog is the way to go. Animoog supports MIDI in, so you can use your own MIDI controller to create the sound or just use the touch interface.
AmpliTube turns your iPad into a multi-effects processor. Not quite something that will replace your gear in a gig environment, AmpliTube can be a great practice aid, especially for the traveling musician who doesn't want to hook up a bunch of gear just to noodle on the guitar. In addition to different amp models and stomp boxes, AmpliTube has tools like a built-in tuner and a recorder. You'll need iRig or a similar adapter to hook your guitar into your iPad and use AmpliTube.
insTuner is a great chromatic tuner that will work with any stringed instrument. The app features the standard frequency gauge as well as a fixed note wheel, which gives you a nice visual feel for the pitch being produced. insTuner supports tuning through the microphone or through line-in modes such as using iRig to hook your guitar into your iPad. In addition to tuning, the app includes a tone generator for tuning by ear. Good alternatives to insTuner include AccuTune and Cleartune.
The metronome is a staple in any musician's arsenal, and Pro Metronome provides a basic metronome that should work fine for most musical needs. The app has an easy-to-use interface that allows you to set the time signature, use it in the background and even use AirPlay to project a visual representation onto your TV.
Guitarists dealing with tablature will love TEFview. This tab library features MIDI playback with speed control, so you can slow it down while learning the song and speed it up once you have it mastered. You can also print out the tab from within the app and share files via Wi-Fi or emailing them as an attachment. TEFview supports TablEdit files in addition to ASCII, MIDI and Music XML files.
Notion is a notation editor that allows for playback using sounds recorded by the London Symphony Orchestra. Notes can be entered using the on-screen keyboard and Notion supports a wide range of functions, including vibrato, bends, slides, harmonics, etc. Notion supports standard musical notation as well as tablature and allows sharing via email. It supports PDF, MusicXML, WAV, AAC and Midi files and can import notation from GuitarPro 3-5.