diff --git a/ports/nrf/mpconfigport.mk b/ports/nrf/mpconfigport.mk
index 7973453c2f..58700817d5 100644
--- a/ports/nrf/mpconfigport.mk
+++ b/ports/nrf/mpconfigport.mk
@@ -20,6 +20,7 @@ CIRCUITPY_AUDIOBUSIO ?= 1
 CIRCUITPY_AUDIOCORE ?= 1
 CIRCUITPY_AUDIOMIXER ?= 1
 CIRCUITPY_AUDIOPWMIO ?= 1
+CIRCUITPY_SYNTHIO_MAX_CHANNELS = 12
 
 # Native BLEIO is not compatible with HCI _bleio.
 CIRCUITPY_BLEIO_HCI = 0