How to Set Crossover Frequency for Speakers

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What is Crossover Frequency

Crossover frequency is the point at which a subwoofer takes over from the main speakers. The crossover point is also the point where the signal is changed in a specific way to feed the different speakers.

As a general rule, a crossover frequency of 80Hz works great with most speakers. This means that the sub is set for 80Hz and the main speakers feeding 80Hz and above. This means that the subwoofer is always going to be pumping out a deeper bass beat compared to the main speakers.

If the crossover frequency is set in a much higher range, the deep bass sound will be coming from the main speakers. As a result, they aren’t able to reproduce the upper-midrange and high-frequency sound as well, which results in a muffled audio quality.

Crossover frequencies of 150Hz, for example, will give the main speakers a hard time. If the speaker is set at 150Hz however, the crossover frequency of the subwoofer is no longer relevant since the subs will be sending out a lower frequency signal than that.

What Are the Types of Crossovers?

Crossovers are speakers filters that give you the option to customize a speaker setup for your audio needs. A typical crossover contains a series of filters based on the frequency range you desire to direct to each speaker.

There are three main types of crossovers: passive, active, and passive component. The passive crossover has the least amount of flexibility and control of the sound production. Passive crossovers are a set of filters that are built into speaker boxes and cannot be retrofitted into factory speaker setups. Passive crossovers require complex circuitry to power each filter individually. An amplifier for each driver is required, which can get expensive and increase the weight of your speaker bundles. This also means that the amplifier controls the volume of each driver, making setup tedious and slow.

Active crossovers are speaker filters that have independent power sources and can be arranged in numerous ways. Since they can be individually powered, you have more control of the independent volume levels of each driver. This makes it easier to mix and match speaker combinations and monitor and mix different sources. However, to power each driver a complex amplifier circuit and speaker wire is required. Active crossovers can be made in a large variety of sizes and shapes and are generally more expensive than a passive crossover.

Active Crossovers

Active crossovers are commonly found on home theater receivers. They allow connection of passive speakers to an active audio/video receiver. Technically, this is called a bi-amp speaker setup. A benefit of active crossovers is that they allow the audio receiver to manage crossover frequencies. In essence, the audio receiver performs the crossover duties. The amplifiers of the speaker drive the low frequencies while the receiver handles the high frequencies.

Front and rear speakers on an AV receiver are most commonly powered by the built-in amplifiers. The amplifiers typically have more power than what the speakers need and the amplifiers contain active crossovers. A crossover frequency can be set from 50 to 200Hz. This sets the upper and lower frequencies that the receiver will send to the corresponding speaker. For example, the receiver will send the lower frequencies of the music to the front speaker amp while it sends the upper frequencies to the rear speaker amp.

After all of the crossovers have been dialed in, front, center, rear speakers, subwoofer and surround speakers can be connected to the receiver using speaker wire. If you’re using separate amplifiers for your front and rear speakers, the active crossover of the AV receiver will be bypassed.

Passive Crossovers

For most home theater systems, you will need to consider a passive crossover. A passive crossover splits the frequencies that each speaker can handle.

For instance, you will likely use four different speaker sizes for surround sound. Each of these speakers will play a portion of the frequency spectrum. A passive crossover separates this frequency and sends it to the appropriate speaker.

Passive crossovers are built into each speaker (or subwoofer) before the amplifier. The crossover splits the frequencies and matches the capabilities of each speaker.

Setting the crossover on the speakers is one of the most important architecture decisions that you have to make. The goal is to set the crossover point where the frequency response is the flattest. If possible, get a frequency response measurement before setting it. Most modern receivers have tools to help you set the crossover.

If you want to learn more about setting an active crossover, take a look at my post about the pros and cons of active vs passive crossovers.

Passive Component Crossovers

Passive crossovers are another kind of filters that are used in many loudspeaker systems. Passive crossovers are used extensively in 2-way and 3-way loudspeaker systems. A passive crossover network separates the incoming power into frequency ranges, applying power to the appropriate speaker driver(s) at each frequency while preventing power from being applied to the others. These crossover networks typically come as a single network for the entire speaker pair or as individual networks for each speaker. Passive crossovers can be combined with an active or powered subwoofer to complete the full system.

The crossover frequencies can be set as low as 60Hz or as high as several kilohertz, depending on the manufacturer. Typically, 2-way loudspeaker systems will use a crossover frequency as low as 200Hz, while 3-way speakers will use frequencies as high as 1kHz. This is because typical manufacturer recommendations for 3-way speaker systems typically use bass-mid-tweeter (BMT) speaker configurations as well. Manufacturer recommendations also change over time, and the numbers will vary from system to system.

The crossover point, or crossover frequency, is the place where power is passed from one speaker driver into another. On a typical passive crossover, you can simply adjust the crossover frequency to match your final speaker combination.

In-Line Crossovers

Crossovers are an important part of any sound system. They separate the different channels of sound and direct them towards appropriate speakers.

When setting up your new sound system, it’s essential to get the crossover frequency right. It’s the main component that dictates how well separate sound channels will blend together. A poorly set crossover will result in a poor sounding dialogue and/or music.

If your system has separate channels with both speakers and a subwoofer, you will need to set the crossover frequency for the entire system, including all speakers. If your system has channels with both speakers and a subwoofer, make sure your system is set up with the two speakers set up in-line with the subwoofer.

If you have separate channels with only the subwoofer and no speakers, or only the speaker with no subwoofer, the crossover frequency will be dictated by the crossover characteristics of the subwoofer.

Which Crossover Types Are the Best?

Crossover selection is the first step in building a custom stereo system or any kind of sound system that you want to sound better. When you are looking to improve the sound of your car audio system, you will have to understand the importance of selecting the right components. One of the most important parts of a car audio system is the crossover. A crossover will help you attain better sound quality by allowing you to match the right speaker to the right drive unit. If you are not familiar with stereo and planning to build a new car audio system, this can be a bit confusing. The simplest type is a passive crossover. You can call this crossover as a first simple electronics filtering network. Passive crossovers are very cheap and that's why they are very popular among car audio enthusiasts.

What Is a Crossover Slope?

Crossovers are used to split high and low frequencies, sending them to their respective speakers (enclosures) of choice. The high-pass filter, which is commonly referred to as the "crossover frequency", is the setting used to make a speaker play only the higher frequencies.

Excursion is the main reason why you use a higher crossover frequency with smaller woofers or woofer drivers. High volume playback causes a cone to move back and forth very quickly, otherwise known as cone excursion. So, if you’re running a 2-ohm (lower impedance) speaker connected to an amplifier, you’re going to be sending that amplifier a low power signal since its impedance is low. Sending it a high pass signal will allow you to send the correct electrical signal to the speaker, allowing it to play with optimal excursion.

So, when it comes to setting a crossover frequency, it really depends on the speaker and the sound quality that you want. You can run a small woofer at a high crossover without sacrificing any of its efficiency.

What Is a Good Crossover Frequency?

Crossover frequencies are settings that come into play when you have multiple speakers, or multiple speaker types. If you've ever heard a sound coming out of your sound system and thought that you could hear two distinct sounds, you could be hearing the crossover frequencies.

There are many different types of speakers, from the tiny tweeters on some high-end speakers to the giant floor-standing models. These speakers all have different frequencies they're most effective at reproducing, and that means low-frequency sound waves should be reproduced by the subwoofer, while the high-frequency ones be reproduced by a tweeter or super tweeter.

And of course, the crossover frequency is where the tweeters and subwoofers meet. When it comes to setting the crossover frequency for your system, you should start with an equalizer, but there are both digital and analog ones that are available. The difference is that an analog equalizer reacts to the sound the speaker outputs, while a digital one adjusts the speaker output itself. The frequency will vary depending on the crossover point required for the speaker system. The crossover point is where the frequency of the tweeter and woofer are set to meet.

With that being said, a good crossover frequency to start with for most systems is around 80Hz. You can find equalizers that change the cutoff frequency range up to 8,000Hz, but the low crossover point is where you need to start.

How to Determine Speaker Crossover Frequency

A speaker crossover network is a circuit that divides an audio signal in two or more frequency bands, each going to a separate driver. It is designed to send high frequencies to a tweeter and low frequencies to a woofer.

Speaker crossovers allow you to place woofers and tweeters of different sizes in the same speaker enclosure. They also allow the speaker to be bi- or tri-amplified.

Choosing the crossover frequency is a matter of matching the driver to the audio range you expect it to be used in. It is not a linear process, so calculations are based on experiments and past experiences. A frequency range of 80 Hz to 120 Hz is ideal for a woofer. While a tweeter should be chosen in a range of 2,000 Hz to 20,000 Hz.

The maximum slope for a tweeter is 6 dB per octave and for a woofer is 12 dB per octave. The minimum octave crossover frequency for a tweeter can be equal to its resonance frequency. This is because the tweeter’s impedance rises with increasing frequency to a high point above the crossover frequency and then falls over the crossover region as the cone becomes more radiating.

Keep your crossovers for your woofers and tweeters as low as possible for better response.

For a more specific setting, however, here’s what you should do.

If you own a stereo receiver with a subwoofer output, you’ll ideally want to set crossover frequency at 80 Hz (for example). This will help the subwoofer blend seamlessly with the main speakers, and you can set the volume for each independently, the optimum setting for each is easy to achieve.

Audio engineers have determined that crossover frequencies are generally at 80 Hz, 100 Hz, 125 Hz, and 160 Hz, regardless of the sound system’s configuration.

However, since you’re setting the subwoofer volume manually, there’s no need to get too specific about the crossover frequency. You can set this general setting based on the speaker’s response.

If your speakers have a gentle downward slope at the crossover frequency (like a 10db/octave slope), follow the same convention and set the crossover frequency at 80 Hz.

If the speakers have a more shallow slope, choose a crossover frequency that sounds good to you. However, if your speakers are self-powered, set the subwoofer to send a -6db signal to the subwoofer (to stay within manufacturers specifications) at the 80Hz setting.

How Can You Set the Phase and Crossover Frequency on a Subwoofer?

The crossover frequency on a subwoofer is the point where the woofer and tweeter (also referred to as a speaker) roles are swapped. The woofer starts to handle the lower frequencies and the tweeter starts to handle the higher frequencies. Crossover frequency is most often measured in Hertz.

So, for instance, if the crossover frequency is around 200 Hz, your tweeter will start to play frequencies above 200 Hz (like 400, 500, 600 Hz and so on). The tweeter will continue to play the higher frequencies until it crosses over to the woofer at around 200 Hz. The woofer will then pick up where the tweeter left off. Basically the tweeter stops handling the high frequencies and the woofer starts to handle the higher frequencies.

So your woofer will play the frequency from 200 Hz to 5000 Hz. This is the frequency range that a tweeter is capable of and that is normally what it will play.

So, in my example the crossover frequency is around 200 Hz. What that means is that your tweeter(s) will start to handle the higher frequencies and your woofer will take over at 200 Hz.

This means that your low frequencies will come directly from your subwoofer and not from your mid or high range speakers. This is very important, because you do not want your low frequencies coming from your mid and high range speakers.

How to Set the Phase

The phase difference of sound waves describes the time difference between the waves when they reach the listener.

When the phase difference matches the wavelength of the sound, these waves combine in a constructive way and a stronger sound is created. When the phase difference partially matches the wavelength, the waves will partially cancel each other and a weaker sound is created.

When the phase difference is 180 degrees out of sync with the wavelength, the waves will completely cancel each other out and no sound will be created.

So what does any of this have to do with sound quality? One big difference between sound waves that are in phase and sound waves that are out of phase is the bass note. When the waves are in phase and the wavelengths partially match, you will experience a heavier or deeper bass note. If the waves are out of phase, the bass note will be weaker.

So if you’ve ever wondered what the crossover frequency is on your speakers and why it’s so important, now you know! The crossover frequency is what determines the phase difference of the sound waves. With proper tuning, you can set the phase difference to make sure your bass notes are aurally satisfying.

How to Set the Crossover

In addition to setting up your crossover, there is another frequency setting that you can adjust. This is referred to as the crossover frequency for your amp. The crossover frequency is the frequency at which your amplifier should stop responding to the signal from your subwoofer or tweeter. Ideally, you would set the crossover frequency as high as possible with the amp still producing sound.

However, this will depend on what the amp is capable of. Generally, you want to set this frequency with the amp producing the highest volume. In addition, it will be best to set the crossover frequency independently for each driver, since the tweeter and subwoofer are not likely to have the same output level.

Also, you must take into account the system impedance of your amp when setting the crossover frequency. The system impedance of your amp is the amount of resistance that the outputs of your amp have. You calculate this by adding together all of the speakers and the subwoofer(s). For example, your amp has a 4 ohms impedance and you have a 2 ohm subwoofer and a 4 ohm main speaker. So total system impedance is 6 ohms.

Some Examples of Outboard Crossovers You Can Buy

A speaker crossover is a device that is installed between the power amp and speaker to control the frequency range that is put through the speaker. Having a crossover in the system gives you a greater degree of control over your speaker system and the low end.

A tweeter is the small active speaker that reproduces the finer sounds and notes in your recordings. These are laid out in the higher frequency range and are usually placed outside of the speaker box for better sound.

A woofer on the other hand, is the speaker that produces the lower bass and volume levels. They do this through a larger surface area. The woofer is usually placed in the speaker's box to assist in making the upper frequencies sound better.

When the speakers are combined, they will produce a wide range of sound on their own. But crossover frequencies are important to limit the frequencies that can be produced through the speakers so that they will both work in harmony. A crossover frequency for speakers can be adjusted by influencing the unit's "slope" or "rolloff," which is essentially how much the frequencies will be attenuated for a specified input.

Should You Install a Crossover Frequency on Your Own?

I’ve recently read where a few people are wondering if they should install a crossover frequency on their car speakers. They do not fully understand how it works and are worried it is too complex for them to correctly install. I thought I would take a little time and explain to them and everyone else reading this.

Should you install a crossover frequency on your car speakers? Well, it is easy and very simple to install. It doesn’t have any type of a wire or a connection to the car. It is fixed in the speaker box. The connection is between the speakers and the amplifier.

The crossover frequency determines which frequencies are delivered to which speaker. It has nothing to do with the car stereo or anything else. All it does is to send to the speakers just the right frequencies to make your car stereo work. If you don’t have the right frequency, the speakers won’t work. Once you know what the speaker is and what the crossover frequency is, it is real easy to install.

Basically, it is just a frequency or a number that you can change that makes one speaker send out the high tones or the low tones. You can change the frequency from a hundred or somewhere close to a hundred, to something like seven hundred and fifty hertz. You can experiment with it to get the right frequency for that type of speaker.

Final Words

When setting crossover frequency, you should listen to the speakers. The frequency response of a particular speaker may change with the volume level, so the crossover frequency should be adjusted as required for the particular speaker.

These settings are related to the characteristics of the speakers. Once a suitable setting has been found, a measured frequency response curve can be further analyzed to gain speaker performance metrics.

If you would like to learn more about setting up a sound system, read our guide on speaker placement and this guide about soundproofing. Also, follow us on Facebook and Twitter for more useful information.