A crossover is a component that is present in almost every loudspeaker with more than one driver in its enclosure. It is responsible for dividing the unfiltered audio signal according to a predefined upper or lower threshold. The speaker crossover supplies each driver with the signal range it was designed to best reproduce. For example, crossovers ensure that tweeters only receive the highest frequencies, not any of the lower ones this driver was not designed to reproduce. This makes a crossover something akin to a loudspeaker’s central nervous system.
There are three basic ways to “crossover” or divide frequencies. These include:
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High-Pass Filter: allows frequencies above the chosen cut-off frequency to pass through to a speaker or group of speakers.
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Low-Pass Filter: allows for frequencies below the chosen cut-off frequency to pass through to a speaker or group of speakers.
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Bandpass Filter: plays frequencies between two points by utilizing both a high-pass and low-pass in the same filter network.
Crossovers optimize loudspeaker frequency response and ensure that each driver produces optimal playback, while ensuring that there are no frequency gaps and that the response is even and linear. Proper crossover configuration is what separates a good sound system from a great one.
Passive crossovers use resistors, capacitors, inductors, or a combination of all three in order to achieve the desired crossover point for a speaker or group of speakers. They are usually less expensive to produce and are typically found in component sets designed by a manufacturer. On the other hand, electronic crossovers are typically more expensive than passive crossovers and offer more capabilities, such as fine-tuning a system with channels of amplification for each individual speaker.
