diff --git a/src/simple-tone-generator.c b/src/simple-tone-generator.c
index 6a3ca33..ff5b2df 100644
--- a/src/simple-tone-generator.c
+++ b/src/simple-tone-generator.c
@@ -10,6 +10,7 @@
 
 #include <math.h>
 #include <strings.h>
+#include <malloc.h>
 #include <assert.h>
 
 #include "simpleaudio.h"
@@ -27,20 +28,16 @@ simpleaudio_tone_reset()
 void
 simpleaudio_tone(simpleaudio *sa_out, float tone_freq, size_t nsamples_dur)
 {
-#define    TONE_GEN_BUFSIZE	(10*48000)	// FIXME
-    float buf[TONE_GEN_BUFSIZE];
-
-    assert ( nsamples_dur <= TONE_GEN_BUFSIZE );
+    float *buf = malloc(nsamples_dur * sizeof(float));
+    assert(buf);
 
     if ( tone_freq != 0 ) {
 
 	float wave_nsamples = 48000.0 / tone_freq;	// FIXME rate
 
 	size_t i;
-	for ( i=0; i<nsamples_dur; i++ ) {
+	for ( i=0; i<nsamples_dur; i++ )
 	    buf[i] = sinf( M_PI*2.0*( i/wave_nsamples + sa_tone_cphase) );
-	    buf[i] /= 2.0;	// normalize (for pulseaudio?) */
-	}
 
 	sa_tone_cphase
 	    = fmodf(sa_tone_cphase + (float)nsamples_dur/wave_nsamples, 1.0);
@@ -53,5 +50,7 @@ simpleaudio_tone(simpleaudio *sa_out, float tone_freq, size_t nsamples_dur)
     }
 
     assert ( simpleaudio_write(sa_out, buf, nsamples_dur) > 0 );
+
+    free(buf);
 }