Xtreme 4th Order Audio Low Pass Filter Board For Subwoofer Amplifiers, Subwoofer Pre Amplifier, 24dB/Octave, 20Hz-150Hz with Phase Switch (0° or 180°) Electronic Components Electronic Hobby Kit Price in India - Buy
AIYIMA Low Pass Filter Bass Subwoofer Preamp Amplifier Board Single Power DC 9-32V Preamplifier With Bass Volume Adjustment - AliExpress
SUB-2 Active Subwoofer LowPass Filter High Quality Freq.40Hz~400Hz+Bass Boost+Phase Control - Motronix