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when the switch is on position, it attenuates the low frequency and reduces the ambient noise for short distance pick-up. B. Sensitivity attenuation: when the switch is on

0 position, it means no attenuation;

when the switch is on -10dB position, it attenuates the sensitivity by 10dB to enhance the SPL, generally it is for high SPL wide dynamic pickup application such as bass frequency drum, trumpet and short distance vocal pickup. ........