-#define AO_BEEP_LOW AO_BEEP_MID * 150 / 94 /* 2500Hz */
-#define AO_BEEP_HIGH AO_BEEP_MID * 75 / 94 /* 5000Hz */
+#ifndef AO_BEEP_MAKE_LOW
+#define AO_BEEP_MAKE_LOW(m) ((uint8_t) ((m) * 150 / 94)) /* 2500Hz */
+#endif
+
+#ifndef AO_BEEP_MAKE_HIGH
+#define AO_BEEP_MAKE_HIGH(m) ((uint8_t) ((m) * 75 / 94)) /* 5000Hz */
+#endif
+
+#define AO_BEEP_LOW AO_BEEP_MAKE_LOW(AO_BEEP_MID)
+#define AO_BEEP_HIGH AO_BEEP_MAKE_HIGH(AO_BEEP_MID)