C# add9 — 8-Voice Polysynth

C# add9 is built from C# – D# – E# – G#. On the 8-Voice Polysynth those tones land as real keys, and every chart below names the tone under each one — root position first, then the shapes that earn their place: inversions, the open spread, the 1-3-7 shell.

The 8-Voice Polysynth allots 8 voices across its 61 keys (C2–C7): enough for most qualities, but the extended colors make the reducer earn its keep — each chart shows the arithmetic.

Under this keyboard's own voice architecture the engine reports: all 4 notes fit — root, 9th, 3rd, 5th.