diff --git a/src/libespeak-ng/readclause.c b/src/libespeak-ng/readclause.c
index 372a7065..902c7ef2 100644
--- a/src/libespeak-ng/readclause.c
+++ b/src/libespeak-ng/readclause.c
@@ -349,7 +349,7 @@ static espeak_ng_STATUS LoadSoundFile(const char *fname, int index, espeak_ng_ER
 			strcpy(fname_temp, tmpnam(NULL));
 #endif
 
-			sprintf(command, "sox \"%s\" -r %d -c1 -t wav %s\n", fname, samplerate, fname_temp);
+			sprintf(command, "sox \"%s\" -r %d -c1 -b 16 -t wav %s\n", fname, samplerate, fname_temp);
 			if (system(command) == 0)
 				fname = fname_temp;
 		}