basic frequency response test. Peak frequencies in Hz of sines measured from this audioboo mp3. Figures in brackets are the source measurements from sine waves: 5043 (17000), 7045 (14999), 10048 (12001), 8003 (7999), 5002 (5002), 3001 (3001), 2001 (2002), 1002 (1000), 500, (502), 200 (201), 101 (99), 49 (51). Results as expected (i.e. close match <12kHz & aliasing at 12kHz and above as SF=22kHz) although there appears to be a dip in the response at 200Hz