The Argon (iPhone 2G/3G/3GS and iPod touch; $1.99) lets you create new sounds by using the included three oscillators, a filter, an amplifier, a saturator and a delay. Also onboard are 64 factory presets and 512 user presets.
Oscillator 1 includes modulatable sawtooth waveforms, a modulatable pulse-width oscillator, modulatable oscillator to triangle wave from sine wave, modulatable noise oscillator and a formant oscillator. Oscillators 2 and 3 include sawtooth, square and sine waveforms, as well as noise. Other features of the oscillator portion include FM and AM, oscillator sync and oscillator modulation.
Filters include lowpass (24dB/octave and 12dB/octave), mid-pass filter, highpass filter, and envelope/LFO.
The Amp section offers overdrive (saturator), 3-band EQ, pan pot and envelope.
With the Delay Effect, you can adjust L/R delay from 0.1 ms to 2,000 ms. This section also includes Tempo Sync mode, left and right feedback, cross feedback, color parameter to control delay sound, an LFO and a spread parameter to modulate phase between left and right channels.
By using the step sequencer, you can make your own pattern; by selecting formant oscillator, you can make audio sound like a human voice.