Using an odd number of unison voices preserves mono compatibility by keeping one voice at dead center

In unison mode, voices are distributed left-right across the stereo field. With an even number of voices there is no center voice — all voices are panned symmetrically away from center, so the signal collapses or thins when summed to mono. With an odd number there is always one center voice (shown in yellow in Serum 2), ensuring the sound retains its core energy in mono. For bass sounds that need to translate well to mono club systems or broadcast, choosing an odd unison count (3, 5, 7) rather than even (2, 4, 6) is the correct practice. The Blend parameter then controls how audible the center voice is relative to the panned outer voices.

Examples

Bass patch in Serum 2: set unison to 4 (even) — the sound may thin in mono. Switch to 5 (odd) — center voice preserved, bass stays solid. For sub-bass, use 1 (trivially mono-compatible).

Assessment

Create a unison patch with 4 voices and listen to it in stereo, then in mono. Note the difference. Switch to 5 voices. Describe what changes in mono. Explain why odd vs even matters.