diff --git a/apps/voice_thread.c b/apps/voice_thread.c
index d0d36b4064..1a86dc7cfa 100644
--- a/apps/voice_thread.c
+++ b/apps/voice_thread.c
@@ -323,6 +323,7 @@ static void voice_data_init(struct voice_thread_data *td)
 
     mixer_channel_set_amplitude(PCM_MIXER_CHAN_VOICE, MIX_AMP_UNITY);
 
+    voice_buf->frame_in = voice_buf->frame_out = 0;
     voice_buf->td = td;
     td->dst = NULL;
 }