LCV Universal Bass Knob Level Controller with Built-in Digital Voltmeter, Blue LED Display, Remote Gain Control, On/Off Switch, Prevent Damage to Your Audio Equipment - Recoil Audio
Remote Bass Level Control Car Subwoofer Controller For Alpine Pwe-s8 Car Speaker Subwoofer - Speaker Accessories - AliExpress
Paradigm X-30 High Pass Subwoofer control unit | Reverb
OSD Black Trevoce 15EQ DSP 1500W Triple 15' Woofers with Native EQ & App Control DSP Room Correction : OSDAudio.com
TARAMPS BASS CONTROL | resilientsounds
Boston Acoustics GTA-RSL Remote subwoofer level control for GTA amplifiers at Crutchfield
Dayton Audio DTA-100LF Desktop Subwoofer Amplifier with EQ
Amazon.com: Nobsound Auto Car Amplifier Audio Subwoofer Bass Control Knob Sub Gain Equalizer Regulator Frequency Controller RCA Line Level Adjust : Electronics
Blue Sky International Star 7.1 Stereo/Subwoofer STAR 7.1 SYSTEM
Audison SR Series SR 1.500 1000W Mono Amplifier with VCR-S1 Sub Volume Remote Control and a Hertz Dieci Series DBX 30.3 12" Woofer in a Sealed Box - Creative Audio
Black Series TreVoce12 DSP 12" Active Subwoofer | OSD Audio
Pyle Active Down Firing Subwoofer - 10 Inches, Ported Design with High-to-Low Input Level Controller, Invisible Down-Firing Speaker, Color Black, Built-in Convenience - PSUB10A - Walmart.com
PSB-1000DSP Subwoofer Amplifier with RS-232 / IR Remote Control, Dual – Soundavo