... , 94dB, 104dB94dB74dB, 84dB, 94dB, 104dB94dBStandard deviation for SPL Smaller than ±0.3 dBSmaller than ±0.5 dBFrequency(Hz)1000Hz1 000Hz, 500Hz, 250Hz, 125Hz1000Hz1 ... 000Hz, 500Hz, 250Hz, 125HzStandard deviation for FrequencySmaller than ±1 %Distortion(THD)≤1 %Power Supplylithium recharge Battery(3.6V ...