restructures audio, begins voicing

quantum/audio/voices.h

@@ -0,0 +1,21 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include <avr/io.h>
+#include <util/delay.h>
+#include "musical_notes.h"
+#include "song_list.h"
+
+#ifndef VOICES_H
+#define VOICES_H
+
+float voice_envelope(float frequency);
+
+typedef enum {
+	default_voice,
+	butts_fader,
+	octave_crunch
+} voice_type;
+
+void set_voice(voice_type v);
+
+#endif