AudioControl's FOUR.1i equalizer takes the old-school in-dash EQ to a whole new level. This little problem solver features 4-band equalization, a parametric bass equalizer, and a built-in line driver that'll send a hot, clean signal to your amps.

Mount the FOUR.1i in your vehicle's dash opening along with your receiver, or under the dash if space is an issue. For connections, you'll find a set of inputs, front and rear outputs, and an auxiliary input for an iPod or other audio source. You can adjust response at 125, 500, 2000, and 8000 Hz, then use the parametric EQ to find and kill any bass trouble spots between 40 and 80 Hz.

AudioControl makes it easy. Bring up your input knob until its LED starts to flicker, then adjust your output level to get the most out of your amplifiers. You can switch between your main and auxiliary sources with the touch of a button. The ground isolation selector allows you to minimize noise in your system. You can choose between green or amber illumination.