Synapse Audio Obsession [WiN, MacOSX]

Key features:
Two part engine with 8 or 16 voice boards.
Single/Dual/Split modes.
High-quality effect block with Delay, Reverb and Chorus.
Precise control of many sound parameters per voice board.
Stepped LFO with freehand drawing for rhythmic sequences.
Scalable GUI, Retina-ready.
Support for Multidimensional Polyphonic Expression (MPE).
420 patches by leading sound designers.