What Is a Speaker Crossover? Complete Guide to Types, Frequencies and Settings (2026)
A speaker crossover is an electronic filter that splits an audio signal into separate frequency ranges and sends each range to the speaker driver built to reproduce it: bass to the woofer or subwoofer, mids to the midrange driver, and treble to the tweeter. Without a crossover, a speaker would sound distorted, and delicate drivers could be damaged. This guide explains what a crossover is, how passive and active crossovers work, what crossover frequency and slope mean, and which settings to use for your system.
The human ear can perceive about 10 octaves of sound between 20 Hz and 20 kHz, which full-range speakers try to reproduce. Most speakers cover only eight or nine octaves, from as high as 20 kHz down to around 40-80 Hz, and some reach lower. Even that range is too wide for one driver to handle alone, so speaker systems use multiple drivers, each responsible for a smaller slice of the spectrum. A two-way speaker divides the full range into two bands:
The high frequencies are handled by a tweeter, while the lower frequencies go to a woofer. A 3-way speaker uses three drivers: a tweeter for the highs, a woofer for the lows and a dedicated midrange driver for the frequencies in between. In some designs, such as floorstanding towers, the speaker may have multiple woofers, since low-frequency notes need more power and cone area than high ones, which calls for extra bass reinforcement.
What is a Speaker Crossover?
A speaker crossover is a circuit used to improve speaker system performance by sending only the frequencies that each speaker driver can reproduce accurately. A crossover divides a full-range audio signal into high, mid and low frequency bands, then sends each band to the driver best suited to reproduce it. Crossovers are built either as circuits inside the speaker cabinet or as processing done before the power amplifier’s input.
If you’re building a sound system, the first step is to roughly decide where the speakers will be placed, followed by speaker selection. To help, we have a guide to the most important speaker specs to consider when buying speakers, and the usual principles of speaker placement. See our Speaker Placement Guide for more.
When Are Speaker Crossovers Necessary?
Multiple speaker drivers work together to provide a full-range audio signal, and crossovers are used in a variety of scenarios. Many sound systems, including home theaters, use multiple speakers.
Each speaker is responsible for accurately reproducing a specific range, or band, of frequencies based on its size, shape and design. Controlling which frequencies go to which speakers via a crossover allows all the speakers in the system to work together to provide the highest possible sound quality. Sending a full-range signal to every speaker, regardless of design, causes problems. To begin with, each driver is only accurate within a certain range. Sending frequencies outside that range wastes the driver’s capacity and produces distorted output. A high-frequency driver can also be damaged by low-frequency energy.
Types of Loudspeaker Drivers
Subwoofer
Subwoofers are loudspeaker drivers with a low-frequency response. A significant volume of air must be moved to reproduce low frequencies effectively, which requires a driver with a large diaphragm area and long excursion. In other words, low-frequency drivers are large speakers capable of big movements. Subwoofers can typically reproduce frequencies from about 20 to 150 Hz. They are typically direct radiator cones with diameters of 8, 10, 12, 15 or 18 inches.
Woofer
Woofers are loudspeaker drivers with a low and mid-range frequency response. They have a design that is nearly identical to that of subwoofers, although they are smaller and have less extreme excursion. Mid-range woofers can produce frequencies ranging from about 60 Hz to 6 kHz. They are direct radiator cones with a diameter of 5 to 12 inches, which allows for more precise reproduction of higher frequencies.
Tweeter
Tweeters are loudspeaker drivers with a high-frequency response. The physical size of a tweeter diaphragm limits its excursion. Fortunately, reproducing high frequencies efficiently requires much less diaphragm excursion than reproducing low frequencies. Horns are frequently used with high-frequency drivers to reduce the required diaphragm excursion. Tweeters are typically dome, ribbon, electromagnetic or piezoelectric drivers that reproduce frequencies above roughly 2 to 5 kHz.
Tweeter Crossover Circuit Diagram
Cross Over Diagram
Common Uses of Speaker Crossovers
There are typically two uses for speaker crossovers: multi-way speaker cabinets and multi-cabinet speaker systems. Both are very common.
Multi-Way Speaker Cabinets
A multi-way speaker cabinet is a single enclosure with several speaker drivers inside it. The image below shows a 2-way speaker. In this enclosure, a woofer reproduces low and mid-range frequencies, while a tweeter reproduces high frequencies.
The term “two-way” refers to the separation of an audio signal into two frequency bands: low-mid and high. Using a crossover, the low-mid frequencies are directed to the woofer, while the high frequencies are sent to the tweeter. Another typical design is the 3-way speaker cabinet, which may feature a woofer for low frequencies, a midrange driver for mid frequencies, and a tweeter for high frequencies.
It’s worth noting that a three-way speaker cabinet can have more than three drivers. Two low-frequency woofers are often used together with a midrange driver and a high-frequency tweeter. The term used to describe the speaker is determined by the number of bands in the crossover network, not the number of drivers.
Multi-Cabinet Speaker Systems
Crossovers are also used to improve the sound quality of multi-cabinet speaker systems that use several speaker enclosures. In these cases, each speaker cabinet is set to reproduce a certain frequency band. A system with a stand-alone subwoofer is a common example of a multi-cabinet speaker system.
Low frequencies are routed to a subwoofer speaker cabinet, which is designed to reproduce only low frequencies in this setup. The remaining frequencies in the low-mid, mid-high and high ranges are sent to a different cabinet. Using a multi-way speaker cabinet for low-mid, mid and high frequencies, plus a separate subwoofer cabinet for low frequencies, is very common.
Speaker Crossover Settings
Crossovers are built from audio pass filters. For example, setting the crossover between a woofer and a tweeter requires a low-pass filter on the woofer signal and a high-pass filter on the tweeter signal. This can be done with electronic components or with digital signal processing (DSP). Low-pass filters let low frequencies pass while reducing, or attenuating, higher frequencies.
High-pass filters allow high-frequency signals to pass while attenuating low-frequency signals. You can learn more about high-pass filters in this article from Audio University. Cutoff frequency and slope are the two primary control settings for low-pass and high-pass filters.
Cutoff Frequency
The cutoff frequency determines the frequency at which a high-pass or low-pass filter begins to work. The image below shows a high-pass filter with an 80 Hz cutoff frequency. The cutoff frequency is commonly the frequency at which the filter reaches -3 dB of attenuation.
Slope
The slope of a high-pass or low-pass filter determines the rate of attenuation across frequency. A filter can be steep or gradual. The following images compare a gradual filter with a slope of 6 dB per octave against a sharp filter with a slope of 24 dB per octave. In audio, the most typical slope values for crossover filters are 12 dB per octave and 24 dB per octave.
6dB/Octave Slope
24dB/Octave Slope
Crossover Point
A crossover system combines two audio pass filters, each with a cutoff frequency and slope. The cutoff frequency and slope determine the crossover point, which is where the two filters meet. The manufacturer sets the crossover point for a speaker cabinet and lists it in the technical specifications or user manual. In many designs the two filters overlap at -3 dB (for Butterworth filters) or -6 dB (for Linkwitz-Riley filters), so that the combined drivers have a smooth, flat frequency response.
The graph below illustrates this. Both filters cross at 80 Hz. The low- and high-frequency drivers each dip at 80 Hz, and the two drivers fill in the gap for each other. This creates a straight line across the graph, which means all frequencies are reproduced at an equal level.
Gain
While gain isn’t technically a crossover parameter, it’s important to understand how it affects the crossover point. Let’s use the same diagram as before. This time, only the low-frequency driver is given a +3 dB boost. As you can see, this frequency driver boost moves the crossover point. The lines now intersect at a frequency higher than 80 Hz. Keep this in mind when setting amplifier gain in an active crossover speaker system.
Types of Speaker Crossover Networks
In sound systems, there are two main types of crossovers: passive and active. It’s important to distinguish between active and passive speakers, which is a separate idea. Here, “passive” and “active” describe how the crossover network is built and where it sits in the signal chain.
Passive Crossovers
Passive crossovers sit between the output of the power amplifier and the input of the loudspeaker drivers. As a result, passive crossovers deal with speaker-level signals, which are much stronger than line-level signals. When using a passive crossover network, one amplifier channel is used to power multiple drivers. The most typical location for a passive crossover is inside the speaker cabinet. They are built from electrical components such as capacitors and inductors, which divide the signal from the amplifier and send the right frequencies to the appropriate drivers. Most passive crossover networks are tailored to a specific set of speaker drivers.
Active Crossovers
Active crossovers are installed before the power amplifier, so they deal with line-level signals. When using an active crossover network, each driver or pair of drivers needs its own amplifier channel. A two-way speaker driven by two amplifier channels and an active crossover is called a bi-amplified system. A three-way speaker system with three amplifier channels and an active crossover is called a tri-amplified system.
Hybrid Crossovers
In many cases, a single system contains both passive and active crossovers. For example, an active crossover could separate low frequencies from mid and high frequencies, feeding the low frequencies to one amplifier channel and the mid and high frequencies to another. The first amplifier channel powers a stand-alone subwoofer, while the second amplifier channel powers a 2-way speaker cabinet. A passive crossover network inside the 2-way cabinet then divides the signal and sends the mid frequencies to the woofer and the high frequencies to the tweeter.
How a Crossover Divides the Frequency Range
How is the full range divided and sent to the drivers? The speaker’s crossover circuit does this using several filters. The circuit accepts a full-range signal from the power amp or AV receiver and sends the high frequencies to the tweeter using a high-pass filter, the low frequencies to the woofer(s) using a low-pass filter, and the middle range of frequencies to the midrange driver using a band-pass filter. A passive crossover is built from simple parts: inductors, capacitors and resistors.
The circuit design, meaning which components are used and how they are laid out, is a key part of the speaker designer’s art. The crossover circuit has a large effect on how the speaker sounds. If a manufacturer uses cheap components and a basic design, the speaker can sound distorted and strained at high volumes, and the soundstage and imaging can suffer. Quality components, careful circuit design, computer modeling and extensive real-world and anechoic testing all help a speaker perform at its best.
Crossover frequencies are used to divide the frequency spectrum into smaller regions, depending on the drivers. Each driver should only reproduce its linear operating range, or its most pleasant frequencies. If a driver reproduces frequencies outside its linear range, it may sound weak or distorted.
In a 3-way speaker, a crossover circuit sends high frequencies to the tweeter, low frequencies to the woofer, and intermediate frequencies to the midrange driver.
Crossover Slope Explained
The transitions between the crossover’s ranges are also crucial. An abrupt transition creates sonic problems, so the transition has to follow the crossover slope. As frequency increases, one filter’s output ramps down and the next filter’s output ramps up. Both drivers reproduce frequencies in the overlapping band between the filters. Say a 2-way speaker’s tweeter-woofer crossover frequency is 2 kHz. Below 2 kHz, the woofer does the work, and above 2 kHz, the tweeter does. As the frequency approaches 2 kHz, the low-pass filter reduces the woofer signal.
At the same time, the high-pass filter brings up the tweeter’s level until it reaches full output above 2 kHz. The crossover slope is the rate at which the woofer and tweeter levels change (sometimes called the rolloff). Many speakers use a slope of 12 dB/octave. Both slopes cross at 2 kHz, 6 dB below their nominal level. Because the tweeter and woofer both reproduce this frequency, they combine to the same level as the higher and lower frequencies, so the speaker’s overall frequency response is flat. Adding a band-pass filter between the low-pass and high-pass filters creates a 3-way crossover, which has two crossover frequencies.
This graph shows the crossover rolloffs of the SVS Prime Pinnacle, a 3-way floorstanding speaker with one tweeter, one midrange driver and three woofers. The woofers and midrange cross over at 320 Hz, while the midrange and tweeter cross over at 2.3 kHz.
The blue curve shows the rolloff of the low-pass filter, the green curve shows the rolloff of the midrange band-pass filter, and the black line shows the rolloff of the high-pass filter. The red line represents the combined frequency response of the full speaker, taking all three filters into account. At the crossover points, each rolloff is 6 dB below the total frequency response.
Recommended Crossover Frequency Chart
The goal of these settings is to ensure each driver is playing within its “comfort zone”, where it is most efficient and least likely to distort. For home theater, 80 Hz is the most common starting point for the subwoofer crossover, and you can fine-tune it from there to suit your speakers and room.
| Speaker Type | Diameter/Size | Recommended Frequency Range | Common Crossover Point |
| Subwoofer | 10″ – 15″ | 20 Hz – 100 Hz | 80 Hz (Low Pass) |
| Mid-Bass / Woofer | 6.5″ – 8″ | 80 Hz – 3 kHz | 80 Hz (High Pass) |
| Midrange Driver | 3″ – 5″ | 200 Hz – 5 kHz | 300 Hz – 4 kHz |
| Tweeter | 0.75″ – 1″ | 2.5 kHz – 20 kHz | 3 kHz (High Pass) |
Designing Crossovers
Crossover frequencies and slopes must match the driver and cabinet acoustics. The crossover circuit also affects power handling. Good designers orient the inductors so their electromagnetic fields don’t interfere, and space the resistors so they can handle more heat and power. You don’t want a speaker that falters as the action peaks. Crossover design is painstaking. First, engineers model a speaker cabinet and drivers using a computer. Then they test a prototype in an anechoic chamber.
Next, they take further measurements in a calibrated listening room that resembles the real world. They listen and make subjective judgments, because a crossover that measures well can still sound bad. Then the design is adjusted and tested again. This iterative process is key to “voicing” a speaker. It should result in a crossover circuit that blends each driver’s sound into a unified whole, so the speaker sounds good in a variety of rooms at any volume. Three filter types are used to split, or “cross over”, frequencies.
High-Pass Filter: Allows frequencies above the cutoff frequency to reach a speaker or set of speakers.
Low-Pass Filter: Allows frequencies below the cutoff frequency to reach a speaker or set of speakers.
A Band-Pass Filter combines a high-pass and a low-pass filter to let only the frequencies between two selected crossover frequencies (one high-pass and one low-pass) through to a speaker or set of speakers.
The slope of a crossover is another factor to consider. The slope is the rate at which the signal rolls off, or attenuates, past the crossover frequency. Slopes are set in 6 dB increments, with the most common being 12 dB, 24 dB and 48 dB, which are found in many amplifiers with variable or fixed crossovers. Advanced DSP tuning processors can offer more options, such as slopes of 6 dB, 18 dB and 36 dB. The steeper the slope, the faster the signal drops past the cutoff. The most common crossover alignment is Linkwitz-Riley, but other alignments, such as Butterworth, can be used with different results.
Active vs. Passive Speaker Crossovers
Active crossovers perform the same function as passive designs, but at a different point in the signal chain. Digital active crossovers split a full-range digital audio signal using DSP (digital signal processing), and the slopes can be chosen by the designer, such as 12 dB/octave. The split signals are then sent as analog signals to separate amplifiers for each driver type. Powered (also called active) speakers with built-in amplifiers use active crossovers. Many Wireless Powered Speaker systems pair a digital active crossover with built-in power amplifiers.
Many of these systems include Bluetooth, WiFi, Ethernet and TosLink optical inputs. The crossover converts analog signals to digital before dividing them into two frequency bands. Powered subwoofers also commonly use a digital active crossover when they receive a full-range signal, which prevents frequencies above the subwoofer’s operating range from reaching the driver. Digital active crossovers can be more precise than passive circuits and can often be adjusted with a software update. Designers also use DSP to optimize speaker performance beyond what a passive crossover can do. Multi-way speakers need crossovers to work properly.
Feeding the right frequency band to the right driver
The function of a speaker crossover can be seen in a 3-way tower speaker. 3-way loudspeakers have a bass woofer, a midrange driver and a tweeter. The loudspeaker receives one unfiltered audio signal. Since sending bass frequencies to a tweeter would distort its sound, and a subwoofer can’t reproduce treble tones, it makes sense to divide the input so each driver only receives the signal it can reproduce best. A well-configured crossover is crucial. Some high-end loudspeakers have high-pass and low-pass filters for adjusting crossovers.
On Teufel’s Ultima 40 Active, the crossover frequency to the subwoofer can be changed manually. A high-pass filter is an electrical filter that lets only high frequencies pass while blocking all frequencies below a specified cutoff frequency from reaching the driver. For bass and midbass drivers, low-pass filters do the opposite.
The image above shows a cross-section of the Definion 5 speaker with its crossover. High-pass and low-pass filters filter signals differently, and their strength is described by “order”. Filters from first to fourth order are the most common. A first-order filter attenuates 6 dB per octave and a fourth-order filter attenuates 24 dB per octave. This all happens inside the loudspeaker and can’t be seen from outside.
Teufel’s Ultima 40 Mk2 is a helpful example of a 3-way design. One tweeter, one midbass driver and two bass drivers reproduce sound between 45 and 20,000 Hz. This covers most of the 20-20,000 Hz range of human hearing. A crossover sends the frequencies to the loudspeaker’s drivers. The drivers are not necessarily placed in order from highest to lowest frequency. In general, the smaller the driver diaphragm, the higher the frequencies it handles. The Ultima 40 Mk2’s tweeter was placed under the midbass driver to improve sound dispersion.
Crossovers optimize loudspeaker frequency response
The crossover is required in all multi-way loudspeakers to achieve an appropriate frequency response. Frequency response is often displayed as amplitude in dB across frequency, usually as a line. This line should have as few spikes as possible, as they detract from the overall sound. After all, the human ear, especially in the midrange, can detect variations as small as one decibel. People who are accustomed to listening to music through high-end loudspeakers will be particularly aware of the differences. Although a perfectly linear frequency response is impossible to achieve in practice, loudspeakers worthy of the “hi-fi” label should not depart from reference values by more than about three dB. A high-quality crossover is necessary for this. To make sure the desired result is achieved, many high-end loudspeaker manufacturers design their own crossovers.
Conclusion: Why the Speaker Crossover Matters for Sound Quality
Crossovers are unseen loudspeaker components that are just as important to good sound as the drivers and the speaker enclosure. One of the most difficult parts of speaker design is configuring the crossover so that each driver plays its best while leaving no frequency gaps, with an even and linear response. Proper crossover design is what separates ordinary speakers from high-end audio systems. If you are setting up your own system, start with the manufacturer’s recommended crossover point, then adjust by ear.
Speaker Crossover: Frequently Asked Questions
What is a speaker crossover?
A speaker crossover is an electronic filter that splits a single audio signal into two or more frequency ranges. It acts as a “traffic cop,” directing high-frequency signals (treble) to the tweeter and low-frequency signals (bass) to the woofer. This ensures that each speaker driver only receives the frequencies it was designed to handle.
Why do speakers need crossovers?
Most speaker drivers are specialized. Tweeters are too small and delicate to handle the high-energy, long-wavelength vibrations of deep bass, and forcing bass into a tweeter can damage it. Conversely, large woofers are too heavy to vibrate fast enough to produce clear treble. A crossover prevents distortion and protects the hardware by filtering out incompatible frequencies.
What is the difference between Active and Passive crossovers?
- Passive Crossovers:
These are the most common. They are built into the speaker cabinet and sit between the amplifier and the drivers. They do not require a separate power source. - Active Crossovers:
These sit between the receiver and the amplifier. They require their own power source and allow for much more precise control. Active crossovers are typically used in high-end home theater setups and professional concert audio.
What is a “Crossover Frequency”?
The crossover frequency is the specific point (measured in Hz) where the signal transitions from one driver to another. For example, if a crossover is set at
2.5 kHz , all frequencies below that go to the woofer, and everything above goes to the tweeter.
What are “2-Way” and “3-Way” crossovers?
- 2-Way:
Splits the signal into two parts: High (Tweeter) and Low (Woofer). - 3-Way:
Splits the signal into three parts: High (Tweeter), Midrange (Midrange Driver), and Low (Woofer/Subwoofer). This results in even better clarity as each driver is even more specialized.
How does “Slope” or “Order” affect the sound?
The “slope” refers to how aggressively the crossover filters out unwanted frequencies. It is measured in decibels per octave (dB/octave).
- 1st Order (6 dB/oct):
A gentle transition. - 2nd Order (12 dB/oct):
The industry standard for most car and home audio. - 4th Order (24 dB/oct):
A very sharp cutoff that prevents any “bleeding” between speakers.
Quick answers: What crossover frequency should I use for a subwoofer? In most home theater systems, 80 Hz is a good starting point, and you can raise it for small speakers or lower it for large towers. Does a crossover affect sound quality? Yes. A well-designed crossover keeps each driver in its comfort zone and blends the drivers smoothly, while a poor one can cause dips, peaks and distortion. Do I need a crossover for a subwoofer? Yes. A subwoofer needs a low-pass filter so it only plays bass, and your main speakers often benefit from a high-pass filter so they do not try to reproduce deep bass.
