​When M12 is plugged into a headphone, the built-in smart detection system will start automatically to detect the headphone impedance and self-adjust to
fit the headphone. Just like the auto shift of a car, M12 will self-adjust to high power level to drive high-impedance headphones with the Gain indicator showing red light, providing excellent dynamic performance. When driving low-impedance and high-sensitivity earphones, M12 will reduce the output level and accurately match their impedance, with the Gain indicator showing green light for low impedance.

Questyle and ESS team spent two years developing the mobile headphone amplifier with DAC and it will perform better than expected. The logo of both Questyle and ESS are put on M12 in order to mark the first cooperation between the two companies. ES9281AC, the ESS flagship USB DAC chip built in M12, has decoding capability up to PCM 384kHz/32bit and DSD256. Whether it is the deepest bass sound of the organ in European cathedrals or the strongest bass and guitar melodies in hard rock, M12 will always be able to capture the details buried deep in the soundtrack.