Xynthesizr is a streamlined yet capable 32-step matrix sequencer/synthesizer with generative features and MIDI.

Whether you are a musician who wants to get inspired and realize their ideas, or a person who enjoys easily creating electronic tunes, this app is for you.
Create patterns and modify them in real time, or let Xynthesizr do it for you using its morphing algorithms. Change scale and key, or transpose within a scale on-the-fly. Tweak parameters of the internal synthesizer or output MIDI to your favorite apps and devices. Record and share your creations.

General features:
◦ MIDI support for syncing and sending notes to synths, samplers and drum machines
◦ Notes to MIDI channel mapping for driving multiple apps or devices simultaneously
◦ Audiobus support
◦ Background audio support
◦ 40+ bundled presets
◦ Save your own patterns and presets
◦ Record and export audio via AudioCopy, AudioShare, SoundCloud®, Mail and iTunes file sharing

Sequencer features:
◦ Gestures to easily edit patterns on-the-fly
◦ [Conway’s Game of] Life-like cellular automata and probability-based pattern morphing
◦ Variable tempo, step length subdivision and pattern length
◦ Selectable keys and scales with ability to transpose in real time
◦ An option to tie consecutive notes of same pitch to make longer notes
◦ Create and use your own scales and Life-like cellular automata rules
◦ Extended range (26 notes for 4-inch screen devices, 22 notes for 3.5-inch)
◦ Color-coded octaves

Synthesizer and FX feature:
◦ 32-bit floating point sound engine
◦ 16 voice polyphony (12 on iPhone 3GS)
◦ 2 antialiased oscillators per voice
◦ 4 waveforms (sine, triangle, sawtooth, square)
◦ 4-pole (24 dB/oct) low-pass resonant filter
◦ 2 ADSR envelope generators (amplitude and filter cutoff frequency)
◦ 2 LFOs to modulate 4 selectable LFO targets (filter frequency, pitch, amplitude, second oscillator detune)
◦ Stereo delay, reverb and randomized panner

Xynthesizr is available for $2.99