Don't let your crossover be the weak link in your car audio chain. AudioControl's 2XS 2-way crossover uses a steep 18 dB per octave slope to separate your high and low frequencies, along with a built-in line driver that'll beef up the signal from an anemic receiver.

The 2-way crossover features one set of inputs and two sets of outputs: high-pass and low-pass. You can change the preset 90 Hz crossover point by installing another AudioControl module, or by modifying the module installed in your 2XS. A built-in filter removes subsonics from your signal so your amps and subs will play louder and cleaner.

Once connected, the 2XS makes it easy — adjust the output knobs until the light indicates 1-volt or 3-volt output, and you're all set. Balanced inputs reject noise caused by your vehicle's electrical system, but internal switching gives you other options for dealing with ground loops.