diff --git a/ports/atmel-samd/common-hal/audiobusio/PDMIn.c b/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
index 8cf86421c9..44129eed12 100644
--- a/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
+++ b/ports/atmel-samd/common-hal/audiobusio/PDMIn.c
@@ -50,7 +50,7 @@
 #include "tick.h"
 
 #define OVERSAMPLING 64
-#define SAMPLES_PER_BUFFER 64
+#define SAMPLES_PER_BUFFER 32
 
 // MEMS microphones must be clocked at at least 1MHz.
 #define MIN_MIC_CLOCK 1000000