This FM Synth has been available on both iPhone and iPad, but the iPad Version now has a perfect interface, great job! as a user I am happy about this free update. it also reacts to velocity! DXi by Takashi Mizuhiki! Thanks a lot, Takashi! I love it. If you ever plan a 6OP-one I buy it instantly. and yes, it is polyphonic! in fact this is like a DX9 Digital Synthesizer , DX27, DX27L and DX21 or DX100.
when notes are played it shows the envelope segments that are played (as a green highlighted time segment).