The DX7IID holds 64 voices in internal memory and an additional 64 voices in a ROM cartridge. Voices can be layered in dual mode providing very rich sounds or a combination of sounds that would be impossible on the original DX7. They can also be split, for a two voice multi-timbral capability.

The stereo outputs allow pans and chorus and a few other nice effects. There are two real time sliders, allowing control of user-programmable parameters in real time. Microtuning, as well as fractional tunings for eastern music etc. is possible.

Specifications
Maximimum Polyphony: 16 notes.
Controllers: breath, sustain pedal, foot 1, foot 2.
61 note keyboard with velocity and aftertouch.
64 patch memories.
Stereo audio out.
MIDI in, out & thru.