SpectrumGen is a bit like the PixelWave experimental synth, but now you can draw the spectrum of sound!
Dark colors - low frequencies (bass). Bright colors - high frequencies.
Key features:
multitouch arpeggiator;
export to WAV (via iTunes File Sharing);
copy to share with another iOS sound apps;
eight predefined timbres;
changeable number of octaves (from 2 to 8);
it is possible to draw the spectrum and play it at the same time;