What Is A Crossover and What Does it Do?

Crossovers are electronics devices that convert a single audio input signal into two or three signals by dividing the signal into bands based on frequencies. So, for example, a single input signal can be separated into bands of low-, high-, and mid- range frequencies. It’s easy to imagine by picturing it as a crossroads with three paths to take and the crossover serving as the sign that points each band of frequencies to its destination.

Why Do You Need A Crossover?

Every audio system, including the one in your car, needs a crossover to direct sound to the correct driver. Tweeters, woofers and subs should get high, mid and low frequencies respectively. Every full-range speaker has a crossover network inside. If these frequencies aren’t directed properly, then speakers will try to play sounds they aren’t meant to play. Mid and bass notes would clash together in the woofers, and tweeters would waste energy playing mid-range notes. In the worst case scenario, some frequencies could disappear completely with others claiming their place.

Types Of Crossovers

There are two crossover types–active and passive. Passive crossovers don’t require power and offer limited control over the volume of each channel. They limit control by allowing the tweeter volume to be adjusted relative to the woofer volume. They are placed between the amplifier and the speakers or sub and, as such, take an already amplified signal to the right driver. These crossovers are usually factory-implemented and are often less accurate, resulting in a sound of a lesser quality.

An active crossover requires an additional power source and is a bit more complicated to install. It goes between the receiver and the amplifier and operates with lower-level, non-amplified signals. In most cases, it enables controlling the relative volume of each frequency band, and of course the frequency steps themselves. Some crossovers also come with an equalizer function. An active crossover allows the amplifier to focus only on the frequencies you need to boost, basically giving you more control over the way your amps act.

Which Type Of Crossover To Choose?

As you might have guessed, an active crossover is a better choice in terms of audio quality. Some car audio systems do have decent passive crossovers but many vehicles come poorly equipped. The best guide is your ear.

If you’re building a custom audio system, active crossovers should be the obvious choice, but they do require a power source. To install it you have to do a bit more planning and spend a little more, but the end result will be an audio system you are fully in control of.