What is Crossover, and How Important Is It?

Crossover is a term we’ve referenced in several of our best lists and is an important component of home audio systems, particularly home theatre systems where the installation is primarily to heighten the movie experience. I’ll explain crossover, how it plays into your sound setup, and why it’s essential; let’s dive in.

What Is An Audio Crossover?

An audio crossover is a circuit that splits the audio signals into various frequency bands, which it then assigns to specific speakers within your setup. Think of it as sound mapping. They form part of a speaker’s design, dictating which drivers each frequency band gets sent to. 

A two-way speaker would split all audio from a track into two groups, highs and lows. It then sends the lows to the woofer or midrange driver and the highs to the tweeter. In a 3-way speaker design, the frequencies are split into three bands instead of two, sending lows to the woofer, mids to the midrange, and treble to the tweeters.

In short, a crossover circuit can improve audio clarity and ensure the most precise sound possible by directing frequency bands to the appropriate drivers.

Passive vs. Active Crossovers

How a crossover unit splits frequencies and the level of control you have over the crossover varies between types. Crossover units can be categorized as either active or passive. Let’s look at how these crossovers differ.

Active Crossovers 

Active crossovers split the frequencies before their amplification and can either form a part of an amplifier or consist of a separate crossover device. Active crossovers allow you to adjust the frequency distribution manually, giving you more control over how your speakers sound. Unlike passive options, active crossovers don’t regulate the frequency distribution across each driver but instead split frequency ranges to different speakers in your setup.

For instance, if you had two midrange speakers that you felt weren’t reproducing sufficient treble frequencies, you could add additional speakers that perform better for your high frequencies and then direct those frequencies toward the new speakers and specify that your previous midrange drivers deal only with the midrange frequencies. They also typically let you adjust things like slope and phase alignment.

Example of an active crossover unit

Passive Crossovers

More common than active crossovers, passive crossovers split the frequency bands between the amp and the driver. These crossovers are built into the speakers and done by the manufacturer. You won’t get the same control in these crossovers, as you cannot adjust the settings. 

Why Crossovers Are Important

With an understanding of what crossovers are and how they work, let’s look at why they’re important and whether you need to consider them for your home stereo.

Frequency Separation

A crossover circuit (passive crossover) is essential for directing the frequencies to specific drivers to refine audio reproduction. By separating frequency bands and sending them to the most suitable driver, the manufacturer can reduce distortion, increase clarity, and provide better depth.

Room Adaption

Each room is different. The shape of the room, the height of the ceilings, and the materials the floor is made from are just a small sample of variables inside of one’s home that can alter the way a speaker sounds.


In the same way that it’s important to match an amplifier to a speaker’s power handling correctly, crossovers help regulate the load on each driver. By separating the frequencies before they reach the driver, the crossover circuit can reduce the strain on the driver, ensuring protection and longevity.

Sound Quality

Passive crossover improves audio quality by producing a more balanced and natural sound. Low-quality crossover can cause transitions between frequencies to lack smoothness and create an uneven sound. The impacts of crossover efficacy can be heard in various ways, with efficient crossovers improving dynamics, tonal quality, and imaging.

Custom Sound Design

An active crossover lets you tailor your audio setup to your own particular preferences. While passive crossovers, as we discussed, don’t allow for manual adjustment – the active crossover can elevate your home audio to the next level and allow you to craft an audio experience unlike any other. Many of these crossovers allow you to adjust the frequency distribution and provide more in-depth control over slope and phase alignment.

How You Can Use This Knowledge

Understanding what crossover is and how it works can be fascinating, as it’s a key factor in audio systems that many casual consumers are not fully versed in. But how can you take your knowledge of crossover technology and turn it into a practical application to improve your sound? There are a few ways…

The first is to determine whether or not your current audio setup needs one. If you have a regular left and right channel setup, there isn’t much use for an active crossover. However, for intricate sound systems that may involve multiple speakers and bi-amping, a crossover will let you refine how your speakers work together. Subtle adjustments to the slope can create a smoother transition, but most crossover effects will be marginal and suited to those looking to get the most out of their setup.

Crossovers aren’t always listed in the specifications in the same way as decibels, sensitivity, or impedance. However, some manufacturers will specify crossover in the following format (*dB/Octave). This refers to the slope and shows the rate at which the amplitude of frequencies outside the intended frequency range is attenuated by the crossover filter. A higher measure in the slope reflects a steeper transition of the frequency band. Consider this when looking at new speakers, as it can provide an idea of the passive crossover.


Passive crossovers are essential components in speakers with multiple drivers, while active crossovers are an optional addition to intricate audio setups where one wants manual control over the frequencies being sent to each speaker. The efficacy of a crossover unit will have a direct impact on the sound quality of a speaker as it relates to frequency distribution and the subsequent impacts thereof.

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Written by
Bryn De Kocks

Bryn De Kocks is the lead editor for Audiostance, as well as one of our trusted reviewers. He has more than 15 years of experience in online publication and stands firm in being transparent with both the benefits and drawbacks of the products he reviews. Outside of editorial work, Bryn has been an avid online gamer and casual digital music producer since his teenage years, bringing his understanding of audio and especially headphones to the table. His daily driver is a humble pair of Fidelio X2HRs powered by a Fiio E10K. In his spare time he enjoys nature photography.

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