diff --git a/lib/main.c b/lib/main.c
index ba4f0c2..b834c43 100644
--- a/lib/main.c
+++ b/lib/main.c
@@ -9,6 +9,7 @@
 #define DEFAULT_RATE 44100
 #define DEFAULT_CHANNELS 2
 #define DEFAULT_VOLUME 0.7
+#define DEFAULT_FREQ 200
 
 #define PWSTREAM_NAME "Dorne"
 
@@ -16,6 +17,7 @@ struct data {
   struct pw_main_loop *loop;
   struct pw_stream *stream;
   double accumulator;
+  uint32_t cycle;
 };
 
 /* [on_process] */
@@ -41,9 +43,11 @@ static void on_process(void *userdata) {
     n_frames = SPA_MIN(b->requested, n_frames);
 
   for (i = 0; i < n_frames; i++) {
-    data->accumulator += M_PI_M2 * 440 / DEFAULT_RATE;
-    if (data->accumulator >= M_PI_M2)
+    data->accumulator += M_PI_M2 * DEFAULT_FREQ / DEFAULT_RATE; // * 440
+    if (data->accumulator >= M_PI_M2) {
       data->accumulator -= M_PI_M2;
+      data->cycle++;
+    }
 
     /* sin() gives a value between -1.0 and 1.0, we first apply
      * the volume and then scale with 32767.0 to get a 16 bits value
@@ -98,11 +102,13 @@ int main(int argc, char *argv[]) {
                         PW_STREAM_FLAG_RT_PROCESS,
                     params, 1);
 
+  // TODO: use pw_thread_loop instead of pw_main_loop
   pw_main_loop_run(data.loop);
 
+  printf("exitting\n");
   pw_stream_destroy(data.stream);
   pw_main_loop_destroy(data.loop);
 
-  return 0;
+  return EXIT_SUCCESS;
 }
 /* [code] */