The international electrotechnical commission IEC581-10 standard high fidelity headphone main performance is: not less than 50 hz to 12500 hz frequency response; Typical frequency response of allowed error of plus or minus 3 db; Frequency response curve of the slope is less than 9 db per octave; Within the 250 hz - 800 hz or so unit into one octave bandwidth and the average sound pressure level difference not more than 2 db. Sound pressure level within the range of 100 hz - 5000 hz to 94 db, the harmonic distortion is less than 1%, to 100 db, no more than 3%;
