Amazon.com: PRV AUDIO Low Pass Crossover 1DF180B Low-Pass Filter for Speaker and Subwoofer Crossover Point at 180 Hz with Unique Selectable Features : Electronics
Focal Sub One Active Subwoofer With Fully Adjustable Low Pass Crossover Black - Zorro Sounds
Amazon.com: PRV AUDIO Low Pass Crossover 1DF180B Low-Pass Filter for Speaker and Subwoofer Crossover Point at 180 Hz with Unique Selectable Features : Electronics