RCF SUB 705-AS MK3 15" Active Subwoofer Drum Tuning just turn the Notch knob

just turn the Notch knob until it goes away

Or you can use the included AudioDesk workstation software for Mac OS

and sturdy

An adjustable shoulder strap is included

RCF SUB 705-AS MK3 15" Active Subwoofer Drum Tuning just turn the Notch knobThe SUB 705 AS mk3 is a portable 15" high power active subwoofer for live sound applications. It features a state of the art transducer with a high power ceramic magnetic circuit and a powerful Class D amplifier that delivers sound pressure levels up to 131 dB with exceptional headroom. Designed as the ideal complement for 10" or 12" loudspeakers, it provides outstanding performance in any application. Rear panel controls include volume, EQ, polarity,