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How to choose a crossover

Send the right signal to your speakers and tweeters

Buck Pomerantz was born and raised in Philadelphia. His parents bought their first television set when he was born. He figured out how to run it by the time he was two. Besides athletics, his formative interests included electronics, amateur radio, music, and stage crew work. He got his BA in writing from Brown University. Then he joined a rock 'n roll band as their soundman and moved to Charlottesville, Virginia. After that venture failed, he spent time in Boston, New Orleans, and Berkeley. He worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems for recording studios, clubs, and bands. He moved back to Charlottesville, ran a little recording studio and finally joined Crutchfield as a copywriter. He has 2 grown children and 3 grandchildren, but after a good nap he can still rock out.

More from Buck Pomerantz

AudioControl 6XS

AudioControl 6XS 6-channel crossover

A crossover is an electronics device that takes a single input signal and creates two or three output signals consisting of separated bands of high-, mid-, and low-range frequencies. The different bands of frequencies feed the different speakers, or “drivers,” in a sound system: tweeters, woofers, and subwoofers.

Think of a crossover network as an audio traffic cop, directing highs to your tweeters, midrange to your woofers, and low bass to your sub.

Without a crossover, a messy, sonic "traffic jam" results. Your midrange and sub duplicate too many of the same frequencies and your sub wastes time trying to put out high notes it wasn't meant to handle. A "fatal pile-up" could also occur, with your tweets being destroyed by some renegade tractor-trailer of a bass note thumping along in the wrong audio lane.

Because they're essential, you'll find crossovers in some form almost any time speakers are present. For instance, if your home stereo uses a pair of 2-way bookshelf speakers, it uses 2-way crossovers (inside the speaker boxes). Within each crossover, a high-pass filter blocks the lows but passes the high frequency notes to the tweeter, while a low-pass filter blocks the highs and passes low frequency notes on to the woofer.

Sound Ordnance P-67CB component system

Sound Ordnance P-67CB component system: woofers, tweeters, and crossovers

The crossover “networks” of coaxial, full-range car speakers are usually built into the speakers, and often consist of small electrical components like coils or capacitors. Crossovers for 3-way systems, those systems utilizing tweeters, midrange drivers, and subwoofers, include, besides high- and low-pass filters, “bandpass” filters which play frequencies between two points by utilizing both a high-pass and low-pass in the same filter network. So, for example you could have a midrange driver only playing 100 Hz to 2500 Hz.

Active or passive?

There are two basic kinds of crossovers: active and passive. Passive crossovers don’t need power to filter the signal as desired. Active crossovers require power and ground connections, but give you much more flexibility and fine-tuning control over your music.

Active systems

A sound system is termed “active” when each driver (tweeter, woofer, sub) has its own channel of amplification. This dramatically increases the available power, dynamic range (softest to loudest sounds), and your control of the system’s tonal response over the whole audio spectrum.

Kicker KX2 2-way crossover

Kicker KX2 2-way active crossover

An active crossover gets wired between the receiver and amplifier and cuts out the unwanted frequencies before the amp wastes energy boosting them, so the amp can focus on only the frequencies you want to hear. Active crossovers usually have volume controls on every channel or pair of channels so you can keep all the “voices” of the different drivers in balance. Some active crossovers include other sound-processing features like equalization for further tweaking of the sound to your personal satisfaction.

The only potential disadvantage of an active crossover is that since it requires +12V, ground, and turn-on connections, it presents more of a challenge to install and set up than a passive crossover. But with a little time and care this shouldn't be a problem, and the rewards and advantages of an active crossover make it clear why you'll find one in virtually every competition-level car audio system. Likewise, stereo systems tuned for high-quality sound will make use of crossovers in order to keep the speakers playing clean and clear.

Passive crossovers

A passive crossover doesn’t need to get hooked up to a power source to work. There are two kinds of passive crossovers: component crossovers that connect between the amplifier and speakers, and in-line crossovers that fit in between the receiver and the amp.

Component crossovers

Passive component crossovers step into the signal path after the amplifier. They’re small networks of capacitors and coils usually installed near the speakers. Component speaker systems come with their crossovers set for optimum performance, and they are simple to install and set up. A full-range signal exits the amplifier and goes to the passive crossover which separates the signal into two parts and sends the high notes to the tweeter and the mid and low notes to the woofer. Most passive component crossovers have optional settings that let you turn down the tweeter some if it seems too loud for the woofer.

Focal Performance PS 165AS crossover

Crossover for a Focal Performance PS 165AS component system

Since it is filtering a signal that has already been amplified, a passive crossover wastes power, releasing the unwanted parts of the amplified signal as heat. Also, speakers actually change their impedances when playing which also changes a passive crossover’s crossover point, or frequency response, leading to inconsistent sound definition, especially around the vocal regions. (This is another advantage to using an active crossover, which is unaffected by speaker impedance.)

In-line crossover

Besides passive crossovers that operate on speaker-level signals and connect between your amp and your speaker components, there are also in-line crossovers that connect before the amplifier. They look like little cylinders with RCA connectors on each end and simply plug into your amplifier’s inputs. In-line crossovers make sure your amplifiers don’t waste energy amplifying signals you don’t want — like high frequencies to a subwoofer amp. Installing an in-line crossover is a great and inexpensive way to sharpen the sounds of your system, especially in a component speaker system.

Bass Blocker

Bass Blocker in-line crossover

In-line crossovers each come set to a specific frequency and can’t be adjusted. Another disadvantage of using in-line crossovers is that they react differently to different amplifiers, possibly changing their crossover points unpredictably.

For future upgrades and expansion, go active

If you plan on expanding your system in the future, it's wisest to go with a separate outboard crossover, instead of relying on the ones built into your receiver and amplifier. While these built-in crossovers work well, they don't offer the total system control of an outboard unit. Also, if you ever upgrade your amp, you don't have to give up your crossover.

Tuning your system

Varying your crossover points is one approach to "tuning" your speakers. You can expect this adjustability from just about any active crossover. Setting crossover points also helps define the overall tonality of your system.

Setting your low-pass filter above 100 Hz gives you the type of boom many rap fans are looking for, while pushing it down to 80 Hz tightens up your bass and improves front soundstaging. Because each output channel on an active crossover usually has its own level control, you can even use this component to compensate for varying efficiency or sensitivity ratings among your speakers.

Stereo 3-way crossover

How a stereo 3-way crossover fits into a system

Let there be music

Let's look at an example. Take a simple three-way crossover network:

  • lowpass filter with a crossover point at 80 Hz;
  • highpass filter with a crossover point at 3,000 Hz;
  • bandpass filter with a low crossover point at 80 Hz and a high crossover point at 3,000 Hz.

You hop into your ride, slip in a CD and suddenly a hefty dose of unadulterated Dave Matthews Band is headed straight for your speakers. The lowpass cleans up Carter Beauford's kick drum and the low notes on Stefan Lessard's bass, and passes these tones below 80 Hz to your subwoofer system.

Meanwhile, your highpass sends cymbal crashes and acoustic guitar harmonics to your tweeter, while limiting frequencies below 3,000 Hz. And Dave's vocals, Boyd Tinsley's violin, and other sounds between 80 and 3,000 Hz find their way through the bandpass crossover to your midrange drivers.

The crossover assigns the proper frequencies and levels to the various speakers in your vehicle, the pieces of the sonic puzzle fit together perfectly, and DMB sounds righteous. It's all good.

Get Everything You Need

You'll need patch cables and power wires to connect an active crossover.
Check out all of the crossovers and other sound processors available at Crutchfield.

  • James from Qatar

    Posted on 6/22/2015

    What are inbiuld crossover

  • Buck Pomerantz from Crutchfield

    Posted on 6/22/2015

    James, A crossover will be describes as 'built-in" when it's located inside a device, like a component speaker or an amplifier.

  • Phill from Texas

    Posted on 7/6/2015

    On point and very helpful. Thanks for the info. I have the Rockford Fosgate BP300 12 which has it's own settings in addition to my Kenwood 501 Head unit. Currently I've set the speakers controls to minimum and using only the Kenwoods settings. Is this the best use of this setup?

  • Buck Pomerantz from Crutchfield

    Posted on 7/7/2015

    Phil, Normally it wouldn't matter, except to say you should use the controls of either one but not both at the same time. But because the low-pass filter of your powered subwoofer can't be turned off, I suggest you turn off all the subwoofer tone controls on your receiver and use only the tone controls (bass boost and X-over) of the subwoofer.

  • israel hall from brooklyn, ny

    Posted on 7/14/2015

    I would like to speak to someone about installing a crossover to my home theater system your help in one's choosing a crossover is quite good

  • Buck Pomerantz from Crutchfield

    Posted on 7/14/2015

    Israel, I don't know why, how, or where a crossover could possibly be utilized in a home theater system. The speakers have crossovers built in, designed by the manufacturer to match the individual drivers. Receivers have built-in crossovers so the subwoofer output will just be bass. This article discusses crossovers used in car audio applications. If you're putting together a home theater system with separate PA-style horns, speakers, and subwoofers, each with its own amp, then you may need to look at a Pro Audio crossover. Give us a call, for help in deciding.

  • Michael

    Posted on 8/10/2015

    Is the epicentre a crossover? How will it affect audio quality?

  • Buck Pomerantz from Crutchfield

    Posted on 8/11/2015

    Michael, The Epicenter by Audio Control is a bass-restoration processor, not a crossover. It uses sophisticated processing to analyze the incoming signal, restore low bass fundamental tones, and increase the bass response.

  • Julius from NAIROBI

    Posted on 8/13/2015

    Does a crossover help to distribute sound to every corner of your car....am experiencing that problem right now my subwoofer loses sound rather the impact its supposed to give...help please

  • Buck Pomerantz from Crutchfield

    Posted on 8/14/2015

    Julius, Crossovers are used to shape signals to match a speaker's ability to reproduce the sound. For example, a tweeter would be destroyed by low-frequencies if a crossover didn't prevent them from playing. For help improving the sound of your bass, check out this article.

  • Ryan McPherson from Fallon, NV

    Posted on 8/22/2015

    What if I have some 3 way crossovers but only have speakers for a 2 way application...woofer and tweeter with no midrange? If I only connect the woofer and tweeter I'll have a gap in my audio range? Can I convert my 3 way to a 2 way?

  • Buck Pomerantz from Crutchfield

    Posted on 8/24/2015

    Ryan, If you're talking about passive crossovers, then I don't think you can convert them from 3- to 2-way. Passive crossovers have fixed separate frequency bands for outputs and there's no easy way to recombine them. There are active crossovers that can switch from one mode to the other. But I've never seen a passive crossover that can do that.

  • Jorge from Caguas

    Posted on 8/31/2015

    Is possible to hook a 30 watts RMS tweeter with a 200 watts RMS midbass speaker in same channel? I heard that only speakers with same size, watts RMS and ohm can be together in same channel cause they need to have the same voice coil to receive equal wattage, in this case the tweeter or the mibass speaker one of them will receive more power (in wattage) than the other and will burn or blown, help me out

  • Buck Pomerantz from Crutchfield

    Posted on 9/1/2015

    Jorge, Assuming there is a crossover to keep low notes away from the tweeter and high notes away from the woofer, you can hook both components to the same amp channel, as long as the amp doesn't put out more than about 50 watts RMS per channel or it'll blow the tweeter.

  • Ronny Mathew from Atlanta, GA

    Posted on 12/1/2015

    I'm having the hardest time finding just a passive crossover. I bought a set of component speakers that came with tweeters, 6.5" speakers, and crossovers, but one of the crossovers has gone bad. Where would I be able to find just the passive crossover? I can't seem to find any here on crutchfield, or anywhere else.

  • Buck Pomerantz from Crutchfield

    Posted on 12/2/2015

    Ronny, Crutchfield does sell some passive crossovers, but they're designed to go with specific woofers and tweeters and you didn't identify yours so we can't tell if any of them would work for you. I suggest contacting your component's seller or manufacturer to see if replacement parts are available.

  • Sahand from Tehran, Iran

    Posted on 1/21/2016

    tnq so much, it was so useful for me, by this information i can install my car audio system myself :)

  • Sean

    Posted on 2/27/2016

    Love the DMB reference. Righteous.

  • George Spotts from Jenkintown, pa

    Posted on 8/2/2016

    Here's what's in my car: A pair of C5-650 components in front doors, a pair of C5-650 coaxials in rear doors, A JL Audio prowedge in the trunk, and a zr midbass driver in the rear deck. What would be a good crossover to buy? Also, I'm thinking about buying a pair of JL Audio 4" mid-range drivers for the rear deck later down the line... Thanks!

  • Buck Pomerantz from Crutchfield

    Posted on 8/3/2016

    George, To control that many different speakers and drivers, I recommend using a multi-channel digital signal processor like the Helix DSP PRO. In addition to being able to set crossovers for up to 10 channels, you'll be able to apply 30-band equalization and time-alignment to each of them as well.

  • Bill from Calgary

    Posted on 8/3/2016

    I'm interested in finding out the type of crossover in my loudspeakers. If I were to provide a schematic in PDF, would you be able to tell me the Order, and Design (e.g. Butterworth, Linkwitz-Riley, etc.)

  • Buck Pomerantz from Crutchfield

    Posted on 8/4/2016

    Bill, You'll get a better answer from the speaker's manufacturer. Reach out to their tech support. Most companies will gladly share knowledge of the technology their products use.

  • William from Las Vegas

    Posted on 9/5/2016

    Hey Buck great tutorial, but I had a question. I'm really interested in buying the AudioControl 6XS, but am currently on a budget so I wanted to slowly build my car system. Before reading your tutorial I was originally planning on buying an amp along with a set of component speakers then getting a separate amp and sub later on with a bi-amp set up. If I were to buy just the component speakers and amp now would I be able swap out the passive crossover on the component speakers for the AudioControl 6XS when I buy the separate amp/sub to complete my system?

  • Buck Pomerantz from Crutchfield

    Posted on 9/6/2016

    William, Yes you can, but the AudioControl 6XS crossover's high-pass frequency comes set at 250 Hz, which seems to me is a bit low for a tweeter's cut-off frequency in an active setup. You can, however, get optional crossover modules from AudioControl to achieve a more appropriate crossover point for your tweeters.

  • Mikhail

    Posted on 9/14/2016

    I need some advice regarding getting my replacement audio setup correctly for my E36 BMW... I decided to go with the JBL CLUB 704 4 channel Amp to replace the stock OEM. Unfortunately this car was designed with a ridiculous amount of speakers (10), 2 door woofers, 2 door tweeters, 2 kick panel mids, 2 rear window mids, and 2 rear window tweeters. It also has a Sub-woofer in the trunk... Based on this, I went ahead and got 2 sets of the JBL GTO509C kits, this covers 6 of the speakers, and addt'ly purchased some 2" woofers from Vifa (NE65W-04) to replace the door woofers... Now I am stuck, there were 2 passive crossovers per JBL kit, however they are only 2 way crossovers... How can I configure this system to run everything?

  • Buck Pomerantz from Crutchfield

    Posted on 9/14/2016

    Mikhail, I suggest using that 4-channel amp to power your front and rear components (with their crossovers) and getting a separate amplifier for those small full-range speakers. Then you can use the onboard high-pass filter to keep bass from distorting.

  • simon from gravesend

    Posted on 11/28/2016

    hi Buck, ive got sony mex-xb100bt, 2x subs swr12d2, 2x amps gm-d9601. i want to add a 2x midrange speakers ~100rms each. if it can be done than, what crossover will suit me best to pump another 2speakers from thoose amps? :) thanks

  • Buck Pomerantz from Crutchfield

    Posted on 11/29/2016

    Simon, You really don't need an additional crossover for your system, both your amps and receiver have crossovers built in. You set the sub amps' low-pass filters to keep highs away from the subs. The Sony receiver has high-pass filters for the front and rear full-range outputs to keep bass notes away from those speakers. Start with both set for around 100 Hz and adjust for the best sound.

  • simon from gravesend

    Posted on 12/3/2016

    hi Buck, thanks for thr answer but.. can u help me to improve it (or make it a bit louder) my music :). thats what ive got: mex- xb100bt. front: xsxb160+sps110tw. rear (behind me on the back seat): xdxb690. boot: 2x swr12d2, 2x gm-d9601. cap: boss audio 8farad. ive still got place in rear doors for speakers. can u suggest me on how to improve it a little bit more? (im just in to it :)) ) regards

  • Buck Pomerantz from Crutchfield

    Posted on 12/5/2016

    Simon, Maybe reading through this tuning article will help.

  • Mason Cocagne from Apple River

    Posted on 12/11/2016

    so say i have a pioneer avh-x4800bs and a alpine pdx-v9 could i get a set of jl audio c2650 components and run the tweeters from that and the woofers from different channels on the amp as long I use the cross over network set up through the pioneer as a active cross over?

  • Buck Pomerantz from Crutchfield

    Posted on 12/12/2016

    Mason, It does appear that that receiver has the ability to use internal crossovers to mitigate all the frequencies to run active as you describe.

  • Jacob from Texas

    Posted on 12/14/2016

    Buck, My wife has a factory JBL system in her car that has tweeter, midrange, and woofer speakers. I want to replace them with the JBL Club 5000C speakers. Where should be the signsl input to the after market JBL crossover comes from? Directly from the amplifer? Or any of those 3 origonal speakers? Thanks

  • Buck Pomerantz from Crutchfield

    Posted on 12/15/2016

    Jacob, We'd have to know what vehicle you're talking about to know for sure, but most of the time when factory speakers are replaced by component sets, the new crossovers get their inputs from the front door factory speaker wiring.

  • William

    Posted on 2/8/2017

    I recently bought some pioneer Ts-a6106c to replace some kicker ks 5.25" components. The pioneers have a crossover but it appears to only filter the audio going to the tweeter. I've got them hooked up to a Hertz hcp4 and am pretty happy with them however I am concerned that the woofer is not being filtered properly....I have the high pass running on the amp but I can't shake the lack of woofer crossover. I guess I'm just asking if I've got it set up properly, and if not, would it be a bad idea to use the crossover from the kickers in place of the one that came with the pioneers?

  • Buck Pomerantz from Crutchfield

    Posted on 2/8/2017

    William, Use the crossovers designed for the particular tweeters and woofers of your new component system. You've given no sound evidence that they're not working, anyway.

  • John from Holmdel

    Posted on 3/6/2017

    Hi Buck I am going to replace everything in a 2004 Mercedes ML 350 with the Bose option. In tryng tomdecide which amp i am confused by this article on crossover selection. The 4 or 5 channel amps only seem to have L and R inputs. Do i need to use multiple mono amps if i am adding an active crossover?

  • Buck Pomerantz from Crutchfield

    Posted on 3/6/2017

    John, Every 4-channel amp I've ever seen has four inputs, and every 5-channel amp has five inputs, so I don't quite understand what you're not seeing. An active crossover goes between a receiver's output and an amplifier's input, whether it's a 1-channel, 2-channel, 4, or 5-channel amp.

  • alan carlson from port orange fl

    Posted on 7/19/2017

    I have a punch 1000x5 and have Vega v468 coaxials x4. Signature Red Surround * 1-inch Aluminum Dome Tweeter * Power Handling: 75W / 400W. * Woofer / Tweeter (in. mm) 6 X 8"(152mm X 203.2mm) / 1.0 (25.4mm). * Frequency Response: 55Hz-20Khz +/-3dB. * Sensitivity: 94dB. * Curvilinear Mica Filled Poly Cone. This Four Ohm VEGA PRO Shallow series 10-inch *Power Handling: 300W / 600W. * Sensitivity (dB @ 1W 1M): 84.5dB. *  75 Watts x 4 + 150 Watts x 1 @ 4-Ohms / 125 Watts x 4 + 300 x 1@ 2-Ohms / 500 Watts @ 1-Ohm 12dB/octave crossover I need some advise on crossover points. My Kenwood DDIN 594 also has plenty of options also. Should I use amp and head unit or stick to one or the other. Thanks so much in advance.

  • Buck Pomerantz from Crutchfield

    Posted on 7/20/2017

    Alan, Do not use the crossover filters on the receiver and the amplifier at the same time. Use one or the other, but not both. The reason is that something called phase distortion generates around each filter's crossover frequency, muddying up the sound. Use whichever controls you feel most comfortable with. A good starting place is with the high-pass filters on the front and rear channels set at 100 Hz, and the subwoofer channel's low-pass filter also set at 100 Hz. You can then fine-tune each to sound best to you. For help tuning your system, check out Tuning your subs.

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