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What is Speaker Crossover

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tweeter crossover

What is Speaker Crossover [ Full Guide Updated Guide 2022]

 

Humans with normal hearing can detect up to 10 octaves of frequencies, ranging from 20 Hz to 20 kHz, and full-range speakers are built to replicate as much of that range as feasible. Most speakers can cover eight or nine octaves, ranging from 20 kHz or even higher at the top to between 40 and 80 Hz, while some can go considerably lower. Although this is significantly less than the complete range of human hearing, it is still a large range, and most speaker drivers can’t cover it all. As a result, most speakers have many drivers positioned within the cabinet. A 2-way speaker, for example, divides the entire frequency range into two smaller ranges, each of which is reproduced by a different driver:

A tweeter is responsible for high frequencies, whereas a woofer is responsible for lower frequencies. Three drivers are used in 3-way speakers to divide the complete range into three smaller ranges: a tweeter, a woofer, and a midrange driver that reproduces the frequencies in the centre between the tweeter and the woofer. Because the lower frequencies require more power to balance the high end, certain speakers, particularly floorstanding towers, include several woofers.

What is a Speaker Crossover?

A speaker crossover is a technique used in audio production to improve speaker system performance by sending only the frequencies that each speaker is designed to reproduce accurately. A speaker crossover divides a full-range audio signal into high, mid, and low frequency components, then distributes each frequency band to the loudspeaker driver that is most suited to reproduce it. Speaker crossovers are made with either circuits built into the speaker cabinets or processing done before the power amplifier’s input.

A speaker crossover is a technique used in audio production to improve speaker system performance by sending only the frequencies that each speaker is designed to reproduce accurately. If you’re creating a sound system, the first step should be to roughly define where the speakers will be placed, followed by speaker selection. I’ve produced two guides that will walk you through the most significant speaker specs to consider when purchasing speakers and the usual principles for speaker placement. If you’d like, you can download the Speaker Placement Guide and the Speaker Specifications Guide.

When Are Speaker Crossovers Necessary?

Multiple speaker drivers work together to provide a full-range audio signal, and speaker crossovers are employed in a variety of scenarios. Multiple speakers are seen in many sound systems.

Each speaker is responsible for accurately reproducing a specified range, or band, of frequencies based on its size, shape, and design. Controlling which frequencies are supplied to which speakers via a crossover allows all speakers in the system to work together to provide the highest possible sound quality. It can be difficult to send a full-range signal to all speakers in a system, regardless of their design. To begin with, each speaker can only be accurate within a certain range. Sending frequencies outside of this range wastes the speaker’s resources and produces erroneous 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 effectively reproduce low frequencies. A speaker with a big diaphragm area and a long diaphragm excursion is required for this. Low frequency drivers, in other terms, are huge speakers capable of large movements. Subwoofers can typically reproduce frequencies between 1 and 150 hertz. Subwoofers are typically direct radiator cones with diameters of 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 capabilities. Mid-range woofers are capable of producing frequencies ranging from 60 Hz to 6 kHz. They’re direct radiator cones with a diameter of 5 to 12 inches that enable 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 significantly less diaphragm excursion than reproducing low frequencies. Horns are frequently employed with high-frequency drivers to reduce the required diaphragm excursion. Tweeters are electromagnetic or piezoelectric drivers that can reproduce frequencies higher than 5 kHz.

Tweeter Crossover Circuit with Diagram to Filter Low Frequency

Tweeter Crossover Circuit Diagram

 

 

Complete Crossover Diagram Example | Audio crossover, Speaker design, Diy boombox

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 of these applications are quite prevalent.

Multi-Way Speaker Cabinets

A multi-way speaker cabinet is a single enclosure with many speaker drivers inside it. A 2-way speaker may be seen in this photograph. A woofer reproduces low and mid-range frequencies, while a tweeter reproduces high frequencies, in this speaker enclosure.

Multi-way-Speaker-1024x576

The word “two-way” refers to the separation of an audio stream 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. A 3-way speaker cabinet, which may feature a woofer for low frequencies, another woofer for mid-range frequencies, and a tweeter for high frequencies, is another typical design.

It’s worth noting that a three-way speaker cabinet can have more than three drivers. Two low-frequency woofers are frequently used in conjunction with a mid-range woofer and a high-frequency tweeter. The term used to describe the speaker cabinet is determined by the crossover network.

Multi-Cabinet Speaker Systems

Speaker crossover systems are also utilised to improve the sound quality of multi-cabinet speaker systems that use multiple speaker enclosures. Each speaker cabinet is set to reproduce a certain frequency band in these circumstances. A system with a stand-alone subwoofer is a frequent example of a multi-cabinet speaker system. L

ow frequencies are routed to a subwoofer speaker cabinet, which is designed to reproduce just low frequencies in this setup. The remaining frequencies in the low-mid, mid-high, and high ranges are sent to a different cabinet. The use of a multi-way speaker cabinet for low-mid, mid, and high frequencies, as well as a separate subwoofer cabinet for low frequencies, is fairly prevalent.

Multi-Cabinet-Speaker-System-1024x576

Speaker Crossover Settings

Audio pass filters are used to build speaker crossovers. A low pass filter on the woofer signal and a high pass filter on the tweeter signal, for example, are required to set the crossover between a woofer and a tweeter. Electronic components or digital signal processing can be used to accomplish this (DSP). Low pass filters let low frequencies pass while lowering or attenuating higher frequencies.

High-pass filters allow high-frequency signals to pass while attenuating low-frequency signals. You may learn more about high pass filters by reading this article or watching this Audio University video. Cutoff frequency and slope are the two primary control settings for low pass and high pass filters.

Cutoff Frequency

The frequency at which a high or low pass filter begins is determined by the cutoff frequency. A high pass filter with an 80 Hz cutoff frequency can be seen in this image. The frequency at which the filter reaches -3dB attenuation is commonly the cutoff frequency.

High-Pass-Filter-80Hz-1

Slope

The rate of attenuation over frequency is determined by the slope of a high or low pass filter. A steep or gradual high pass or low pass filter might be used. A gradual filter with a slope of 6dB per octave is compared against a sharp filter with a slope of 24dB per octave in the following photos. In professional audio, the most typical slope values for crossover filters are 12dB per octave and 18dB per octave.

6dB/Octave Slope

High-Pass-Filter-80Hz-6dB-1024x342

24dB/Octave Slope

High-Pass-Filter-80Hz-24dB-1024x344

Crossover Point

A crossover system combines two audio pass filters, each with a cutoff frequency and slope. Cutoff frequency and slope determine the crossover point. Crossover is where two filters meet. The manufacturer determines the crossover point for a speaker cabinet and lists it in the technical specifications or user manual. Ideal crossover point is when two filters overlap at -3dB. The coupled drivers will have a smooth frequency response.

This graph illustrates. Both filters cut off at 80 Hz. Low and high frequency drivers both dip -3dB at 80 Hz. 3dB is half the power output, therefore the two drivers will fill the hole. This creates a straight line across the graph, suggesting that all frequencies are equal.

Crossover-80Hz-1024x343

Gain

While gain isn’t technically a crossover parameter, it’s crucial to know how it influences the crossover point. Let’s utilise the same diagram as before. This time, only the low frequency driver will be given a +3dB boost. As you can see, the crossover point is moved by this gain enhancement. The lines are now intersecting at a higher frequency than 80 Hz. When setting the amplifier gain in an active crossover speaker system, keep this in mind.

Crossover-80Hz-3dB-Lows-1024x344

Types of Speaker Crossover Networks

In sound systems, there are two types of crossovers: passive and active. It’s important to distinguish between active and passive speakers. The method for building a crossover network is described as “passive and active” in this case.

Passive Crossovers

Passive-Crossover-Network-1024x576

Between the output of the power amplifier and the input of the loudspeaker drivers are passive crossovers. As a result, passive crossovers deal with speaker level signals, which are substantially stronger than line level impulses that travel via an audio mixer. One amplifier channel is utilised to power numerous drivers when employing a passive crossover network. The most typical location for a passive crossover is within the speaker cabinet. Electrical components such as capacitors and inductors are used to construct them. The signal from the amplifier is divided by these electrical components, which then transfer the frequencies to the appropriate drivers. The majority of passive crossover networks are tailored to a single speaker driver.

Active Crossovers

Active-Crossover-Network-1024x576

Before the power amplifier, active crossovers are installed. Active crossovers deal with line level signals as a result. When employing an active crossover network, each driver or pair of drivers requires its own amplifier channel. Biamplified systems are those that have a two-way speaker driven by two amplifier channels and an active crossover. Triamplified systems, on the other hand, are three-way speaker systems with three amplifier channels and an active crossover.

Hybrid Crossovers

Hybrid-Crossover-Network-1024x576

In many circumstances, a single system contains both passive and active crossovers. An active crossover, for example, could be used to separate low frequencies from mid/high frequencies by feeding low frequencies to one amplifier channel and mid/high frequencies to the other. A stand-alone subwoofer is powered by the first amplifier channel, whereas a 2-way speaker cabinet is powered by the second amplifier channel. A passive crossover network divides and distributes the mid frequencies to the woofer and the high frequencies to the tweeter inside the 2-way speaker cabinet.

Divide Frequencies and Conquer Accurate Sound

How is the complete range divided and sent to drivers? The speaker’s crossover circuit, which has many filters, does this. This circuit accepts a full-range signal from the power amp or AV receiver and delivers the high frequencies to the tweeter using a highpass filter, the low frequencies to the woofer(s) using a lowpass filter, and the middle range of frequencies to the midrange driver using a bandpass filter (see Fig. 1). Passive crossovers are straightforward. It has inductors, capacitors, and resistors.

The circuit design—which components are used and how they’re laid out—is a key part of the speaker designer’s art. SVS engineers focus on the crossover circuit, which affects the speaker’s sound. If a manufacturer uses cheap components and a rudimentary design, the speaker can sound distorted and strained at high volumes, and the soundstage and image can be impaired. SVS combines premium components, advanced circuit design, rigorous computer-aided modelling, and extensive real-world and anechoic testing to deliver uncompromised speaker performance.

The 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 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 transmits high frequencies to the tweeter, low frequencies to the woofer, and intermediate frequencies to the midrange driver.

Slippery Slope

The crossover’s range transitions are also crucial. A quick transition generates sonic issues, thus it must follow the crossover slope. As frequency increases, one filter’s output ramps down and the next’s ramps up. Both drivers replicate frequencies in the overlapped frequency bands of the filters. Say a 2-way speaker’s tweeter-woofer crossover frequency is 2 kHz. Below 2 kHz, the woofer is used, and above 2 kHz, the tweeter. As low frequencies reach 2 kHz, the lowpass filter reduces the woofer signal.

At the same time, the highpass filter boosts the tweeter’s volume until it peaks over 2 kHz. The crossover slope is the rate at which woofer and tweeter levels change (sometimes called the rolloff). Slope is 12 dB/octave in most SVS speakers. Both slopes cross at 2 kHz, 6 dB below their nominal level. Because the tweeter and woofer both reproduce this frequency, they reach the same level as higher and lower frequencies, thus the speaker’s overall frequency response is flat. Adding a bandpass filter between the lowpass and highpass filters creates a 3-way crossover (see Fig. 2). Two crossover frequencies exist.

Prime Pinnacle Speaker Crossover Chart

The crossover rolloffs in the SVS Prime Pinnacle, a 3-way floorstanding speaker with one tweeter, one midrange, and three woofers, are depicted in this graph. The woofers and midrange crossover at 320 Hz, while the midrange and tweeter crossover at 2.3 kHz.

The lowpass filter’s rolloff is shown by the blue curve, the midrange bandpass filter’s rolloff is represented by the green curve, and the highpass filter’s rolloff is represented by the black line. The aggregate frequency response of the full speaker, taking all three filters into account, is represented by the red line. At the crossover points, the rolloffs are 6 dB lower than the total frequency response.

 

Designing Crossovers

Crossover frequencies and slopes must match driver and cabinet acoustics. The crossover circuit also impacts power-handling. In SVS crossovers, the inductors are perpendicular to each other so their electromagnetic fields don’t interfere, and the resistors are vertically spaced so they can handle more heat and power. You don’t want a speaker who falters as the action peaks. Crossover design is tedious. First, our engineers model a speaker cabinet and drivers using a computer. Then they test a prototype in an anechoic chamber.

In a calibrated listening room that resembles the real world, they take further measures. They listen and create subjective judgements. Despite measuring properly, a crossover may sound bad. Then we alter the design and try again. This iterative procedure is key to “voicing” a speaker. It should result in a crossover circuit that mixes each driver’s sound into a unified whole, so the speaker sounds wonderful in every room at any volume. All passive SVS speakers use a SoundMatch crossover to offer a broad soundstage with accurate frequency response and precise imaging. The SoundMatch crossover mixes each driver flawlessly for superb on- and off-axis frequency response and accurate spatial imaging. All Prime and Ultra Series devices are timbre-matched to blend easily for maximum system flexibility. Three methods split or “crossover” 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 Crossover to allow sounds above and below two selected crossover frequencies (one High Pass and one Low Pass) to pass through to a speaker or set of speakers.

JL Audio Crossovers

The slope of crossovers is another factor to consider. The rate at which the signal rolls off or attenuates past the crossover frequency is known as the slope. Slopes are set in 6 dB increments, with the most common slopes being 12 dB, 24 dB, and 48 dB, which are found in many amplifiers with variable or fixed crossovers. For more advanced tuning, higher-end DSP tuning processors like the TwKTM 88 and TwKTM D8 provide slopes of 6 dB, 18 dB, and 36 dB. The steeper the slope on the crossover, the greater the decibel. The most common crossover slope is Linkwitz-Reilly, but other types of crossover slopes, such as Butterworth, can be employed with varying outcomes.

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). Like a passive crossover, the crossover slope is 12 dB/octave. The analogue split signals are supplied to separate amplifiers for each driver type. Powered (aka active) speakers with built-in amplifiers use active crossovers. 2-way SVS Prime Wireless Powered Speaker System with a digital active crossover and 200-watt (50 x 4) power amplifier.

Bluetooth, WiFi, Ethernet, and TosLink optical inputs are included. Crossover converts analogue signals to digital before dividing them into two frequency bands. When receiving a full-range signal, SVS subwoofers use a digital active crossover. The crossover prevents frequencies above the subwoofer’s operational range from reaching the driver. Digital active crossovers are more accurate than passive circuits and can be modified with a software update. SVS uses the same iterative measuring and listening procedure to fine-tune its active crossovers, and engineers can employ DSP to optimise speaker performance beyond a passive crossover’s capabilities. Multi-way speakers need crossovers. SVS speakers are designed to disappear, leaving only immersive sound.

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, midrange driver, and tweeter. The loudspeaker gets 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 best reproduce. Well-configured crossover is crucial. Some high-end loudspeakers have high and low pass filters for adjusting crossovers.The Ultima 40 Active's sub crossover

On Teufel’s Ultima 40 Active, the crossover frequency to the subwoofer can be manually changed. A high pass filter is an electrical filter that lets only high frequencies pass while blocking all lower frequencies below a specified cutoff frequency from reaching the driver. For bass and midbass drivers, low pass filters have the opposite effect.Teufel's Definion 5 speaker crossover

Cross-section of Definion 5 speaker displaying crossover. High and low pass filters filter signals differently. “Orders” describes them. First- and fourth-order filters are most common. A first order filter can block 6 dB and a fourth order filter can block 24 dB per octave. This happens inside the loudspeaker and cannot be seen. Learn about high and low pass filters in this video.

Teufel Audio’s Ultima 40 Mk2’s 3-way design helps visualise a crossover. 1 tweeter, 1 midbass driver, and 2 bass drivers reproduce sound between 45 and 20,000 Hz. This covers the 20-20,000 Hz human hearing range. A crossover sends the frequencies to the loudspeaker’s drivers. This speaker’s drivers are not placed from highest to lowest frequency transducers for optimal sound. The driver’s circumference determines its function. Less circumference, more frequency. 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 loudspeakers to achieve an appropriate frequency response. The frequency response is often displayed as a frequency amplitude in dB. Frequency response is commonly represented visually as a line. This line should have as few spikes as possible, as they will detract from the overall sound. After all, the human ear, especially in the midrange, is capable of detecting variations as little as one decibel. People who are accustomed to listening to music through high-end loudspeakers will be particularly aware of the differences. Although a totally linear frequency response is impossible to achieve in practise, loudspeakers deserving of the moniker “hi-fi” should not depart from reference values by more than three dB. A high-quality crossover is necessary for this. To ensure that the desired impact is obtained, many high-end loudspeaker manufacturers will configure their own crossovers.A cross-section of the Definion 5 stereo speaker

 

Coda: The speaker crossover separates the audio signal for optimal playback

Crossovers are unseen loudspeaker components that are just as important to a nice sound as the drivers and the speaker enclosure. One of the most difficult aspects of speaker design is configuring the crossover so that each driver produces excellent playback while guaranteeing that there are no frequency gaps and that the response is even and linear. In this approach, proper crossover arrangement is what distinguishes ordinary speakers from high-end audio systems.

 

 

 

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