What is a crossover filter (HPF and LPF)?

A crossover filter is used to determine which frequencies a speaker should play.

Different speakers are designed for different frequency ranges. For example, a tweeter reproduces high frequencies, whereas a subwoofer is built to play the lowest frequencies.

With the correct crossover filter, you can improve sound quality and reduce the risk of speakers being exposed to frequencies they are not designed to handle.

What do HPF and LPF mean?

• HPF (High Pass Filter): A high-pass filter that passes frequencies above a selected limit and attenuates lower frequencies. Used, for example, to protect tweeters, midrange drivers and door speakers from excessively low frequencies.

• LPF (Low Pass Filter): A low-pass filter that passes frequencies below a selected limit and attenuates higher frequencies. Mainly used for subwoofers.

• BPF (Band Pass Filter): A band-pass filter that combines high-pass and low-pass filtering to restrict the speaker to a particular frequency range.

What are crossover frequency and filter slope?
The crossover frequency indicates where the filter starts attenuating the signal. The filter slope indicates how quickly attenuation increases outside the selected frequency range.

Filter slope is usually expressed in dB per octave, such as 12 or 24 dB/octave.

A 24 dB/octave filter attenuates more quickly than a 12 dB/octave filter.

Which crossover frequencies should I use?
This depends on the speakers’ design, the installation and your sound system.

Always start with the speaker manufacturer’s recommendations. Incorrect crossover settings can worsen the sound and, in some cases, damage the speakers.

Need help with crossover filters and audio settings? Contact our customer service team or one of our stores.