There are hundreds of ready-to-use scales included ? from common ones like major and minor to Javanese Pentachord ? putting music-making within reach of amateurs. It's actually a bit of a challenge to play something that sounds bad. Shape your tunes further by moving your iPad. Shake for vibrato, for example. Recording and sharing options aplenty make it easy to let others sample what you've made.
5. Bloom HD
At first glance this app appears to be nothing more than a stream of cool tones ? some triggered by you, others played by the app itself ? accompanied by visual bubbles. But that's like mistaking yoga for mere stretching. What's on offer here is a new kind of audio/visual instrument cooked up by ambient sound guru Brian Eno.
You start by listening and looking at the app, which gradually takes on a trance-like, zen flavor. Swirling your finger in this multimedia koi pond by tapping the screen and watch as your finger placement generates its own sounds and circles. Every action you do contributes to the layers of sound ? bridging the gap between instrument and multimedia experience. The app feels part your creation and part travel to EnoVille.
6. Bubble Harp
This odd, charming app will fascinate as many people as it frustrates. The developer calls it "a combination of drawing, animation, music, art, geometry, and gaming. You can record long movements of a single point, or stream many points out of your fingertips like ink."
Practically speaking, what you'll mainly do is swipe the screen and watch the pulsing line (representing the current note being played) spider across the web you've helped make. Tap the note-shaped icon to adjust the chords that play. It's wacky; it's wonderful; it's worth a buck or two.
Today's DJs work digitally and you can too with this portable beat-spinning station. What's most impressive is what's within reach of newbie MCs. After familiarizing yourself with the cockpit-complex console (flatten the learning curve by checking out some tutorials), the soundscapes you can create are stunning. Fill up to eight tracks with an almost infinitely customizable assortment of loops.
You can pick these loops from a few dozen that come free with the app or buy genre-specific collections: hip hop, reggae, and so on. When you've got your track collection all set, save it so you can start sequencing. This final step is where you stitch together and then export your tune as a high-quality version of the mix you've made.
The name of this app perfectly captures the service it aims to provide. Yes, it's got a bunch of mechanical noise replicas (white noise, train tracks), but what it's really good for are all things melodious: wind chimes, zen tones, flutes and pleasant interpretations of themes like "Immersed," "Night" and the slightly tautological "Melody." Play each sound separately or mix them together by using the simple tap-to-activate controls. A built-in sleep timer and favorites list make this some easy listening that you'll actually want to turn on.
Peter Meyers is a digital book producer and the author of Best iPad Apps (O'Reilly Media). He's covered the intersection of writing and technology for The New York Times, The Wall Street Journal, and Wired and blogs at anewkindofbook.com.