#define REDUCE_FACTOR 29163// -1 dB 	0.89x(2^15)
#define INCREASE_FACTOR 18399	// +1 dB	(1.123/2)x.....
#define MIN_VOLUME 327	// -40 dB	0,01x.....
#define MAX_VOLUME  32767	//   0 dB	1x......

extern void process_data();
extern void reduce_volume();
extern void increase_volume();