One of my favorite things to do with my iDevices (iPhone, iPad) is to use them for musical creation. IKMultimedia makes some great tools to work with music and iOS. Two of my first purchases were the iRig and the iRig Midi. These two devices together with a midi keyboard controller (with onboard sounds, otherwise you have to use the iPhone for the module which can create an odd loop) can make for a powerful perfomance setup.
The way I like to set things up is to have a keyboard with onboard sounds. I use the line out and run that into the iRig line in. This creates a recording interface for your samples. Next I connect the Midi In and Out into the iRig Midi from the keyboard. This provides the midi controller with its note on/off connections.
Now that we have the apps installed and everything connected we can start playing. SampleWiz has some great effects to play with, but the important part for this setup is the Sampler (of course!). The Red Record button on the app will allow you to record your sounds directly from your keyboard. This is why I recommend a keyboard with onboard sounds. Recording directly into SampleWiz will get you nice clean tones. So if you play a phrase and record it, you’ll now only have to push one note to play that whole phrase. SampleWiz transposes the notes for you. Using SampleWiz’s overdub sampler you can even sample a sample and create some very interesting loops. (SampleWiz does however have a 10 sec loop max.) If you are looking for a longer loop recording time, you can do something similar with garagebands sampler as well. The other key use of this setup is to record your own samples. I like to record my friends guitar sounds to create my own presets. Just make sure you have them play Middle C when recording to get the widest range of notes without the app making things sound too processed. Keep in mind your software is doing the transposing, so the high and low notes do sound a bit processed sometimes.
This is great to create an effect type sound like used on Pink Floyd’s dark side of the moon. (4:10)