Twisted Electrons has released a SID synthesizer for iPad, with a fairly authentic sounding Commodore 64 feel. It manages to be very dirty and very digital at the same time.
SidPad iTunes Description:
SIDPAD is a flexible 8bit style synthesizer offering many features:
- 3 Voice Synthesizer
Over 40 controllable parameters to create a wide range of 8 bit chip-tune sounds. All knobs midi controllable!
- Multimode Filter
includes Type, Cutoff, Resonance and customizable Cutoff Envelope
- Flexible Modulation
Hand draw up to 4 graphs and assign them to the synth's parameters to add movement and expression to your sound
- Wavetable Editor
The 16 step wavetable editor is a great tool to set up sound effects and arpeggiated melodies.
You can sequence notes and waveform changes either as one shot or in a loop and vary the speed
- Help Mode
Every feature is explained via the help button to get you up and running with SidPad regardless of your synthesizer experience.
Like Studio 1111 it is free to try, but will nag you to upgrade to Pro ($4) for all the features including MIDI.