The HFEQ is great active EQ product which permits your favorite iPodr type device to play thru your amplified car audio system. Featuring an audio input selector for switching between a headunit & another sound source, a matching headphone plug to stereo male RCA adapter is all that"s needed to plug in your MP3 players headphone jack. The EQ"s independent input-level controls for both the car radio & any device like an MP3 player insure identical volume levels when switching between either audio input. A handy Master Volume gives you total control of the SPL-level of both sound sources. A 9-Volt Line-Driver The Hifonics HFEQ is a half-DIN, ISO mounting 4-band, 9-Volt line-driver preamp EQ w/front/rear active crossover features & extensive subwoofer crossover controls. The HFEQ"s "Line Driver" circuit delivers a whooping 9-Volts of preamp level signal through the RCA"s. Any consumer wishing to get the most out of their add-on amps & subwoofer system needs the HFEQ. The HFEQ"s small 1/2 DIN size permits many mounting locations. All non-in-dash installs will find the Hifonics HFEQ"s small-size chassis handy to install. Especially into center / overhead consoles, glove boxes or in any 1/2 DIN pocket opening. Hifonics HFEQ Use To Connect An iPodr * 1/2 DIN, ISO Mount Chassis * 4-Band Equalizer w/+18dB Variable 9-Volt RMS Line-Driver Preamp Output * Master Volume & Subwoofer Volume Control * Front to Rear Dual-Amp Fader * 2-Audio Inputs w/Level Matching * Selectable 12dB High-Pass F/ R Crossover * Selectable 12dB Low-Pass Sub Output * Selectable for Mono or Stereo Subwoofer Setups * EQ w/12dB of Boost / Cut: * 45Hz Sub-Bass Control * 120Hz Mid-Bass Control * 2.2KHz Mid-Range Control * 12KHz Treble Control