How To Design And Build A Speaker Crossover – DIY Guide With Diagrams!

Welcome! In this big how-to guide, I’ll show you how you can design and build your own speaker crossover for home or car audio.

I’ve built many of my own – from basic ones to more advanced designs so I’d love to share what I’ve learned along the way. I’m going to cover quite a bit so let’s dig in!

What this how-to guide covers

what is in this article section image

There are so many different types and variations of passive crossover design types that it’s not practical for me to cover all of them. To keep things manageable and help the highest number of people (just like you!), I’ll cover what you need to know for building one of several options that will work for 95%+ of speaker system needs.

How this article will help you

My article will provide the know-how, diagrams, info, and steps to build a do-it-yourself (DIY) speaker crossover for getting the sound you want based on my own real-world experience doing so. It’s entirely possible to build something you’ll enjoy using and be proud of without huge headaches or going broke!

In this how-to guide I’ll cover:

  • 1-way (tweeter high pass or woofer low pass), 2-way, and 3 way crossovers.
  • Good first order and second order crossover design types to use.
  • How to determine the cutoff frequency (crossover frequency) numbers you’ll need.
  • Schematic diagrams to help you build yours which you can download or print if you like.
  • What you need to know about speaker impedance (speaker Ohms) and why it matters.
  • Choosing the right parts to buy and a practical approach to part values.
  • What to do if you can’t find the right part values.
  • Wiring up your crossover network and assembling everything (without having to build a custom circuit board).
  • Additional things to do for that extra touch and even better performance.

(Feel free to skip some sections if you’re not new to some of the ideas here.)

Note: As this isn’t intended to be a more advanced article I won’t cover a few technical aspects like voice coil impedance, phase response, sound wave off-axis response, phase shift, or 4th order design options.

How does a passive crossover work? (A brief guide for beginners)

Examples of 2 way crossovers and diagram

A passive crossover filter differs from an active crossover (used in electronic audio designs, amplifiers, and preamplifiers, etc.) in that it uses non-powered passive components to filter out a frequency range before it can reach a speaker. In practical terms, they effectively “block” unwanted sound frequencies from reaching a speaker driver by greatly reducing, or attenuating, the input signal from a stereo or amplifier.

This is possible due to a property of capacitors and inductors called reactance. Reactance, in short, describes the physics properties that create opposition to the flow of electrical current which also changes with the audio signal frequency.

In other words, this creates an impedance, or opposition, to the speaker voltage and therefore can pass or reduce audio power to a speaker terminals.

examples of speaker crossover capacitor and inductor

The role of capacitors and inductors in crossover network design

  • A capacitor increases its opposition to the flow of current at frequencies below the crossover point. This means it acts as a high pass filter when connected in series with a speaker load (Ohms load).
  • An inductor increases its opposition to the flow of electricity more at higher frequencies above the crossover point. This means it acts as a low pass filter when connected in series with a speaker.

The real-world uses for these are extremely important in home audio or car audio speaker systems:

  • We can use the right value capacitor (rated in units called Farads) to prevent low frequency sound from reaching a tweeter which would cause distortion or even damage!
  • We can use an inductor of the right value (rated in units called Henries) to prevent high frequency musical signals from reaching a woofer which would sound very poor or harsh.

Capacitors and inductors can be used alone (single stage crossover, also called 1st order) or combined to make an even more effective filter with different characteristics. 1st order crossovers have a crossover slope, or filtering steepness/effectiveness, that rolls off at a rate of 6 dB per octave.

Second order crossovers, which have two capacitor or inductor sections, roll off their output at 12dB per octave. 2nd order designs are one of the most commonly used for passive crossovers as they’re a good compromise between complexity, cost, slope steepness, and sound quality.

what is a crossover slope diagram no title

We use Decibels (dB) in the engineering world we use Decibels to measure speaker output levels or audio crossover signal values because both are non-linear. This means that for audio they increase or decrease based on powers of 10 (a.k.a., they’re logarithmic).

A negative sign in front indicates a reduction where a positive sign or none in front indicates a gain.

Ex.: A crossover with a slope of -6dB/octave will have an output that’s reduced by 6 dB for each octave (a halving or doubling of frequency: 400Hz, 800Hz, 1,600 Hz, etc.) past the cutoff frequency.

What is a speaker crossover point?

A speaker crossover point is usually called a crossover frequency and it’s sometimes written as “Fc” to represent the “cutoff frequency.” A speaker crossover point is the cutoff frequency beyond which audio frequencies are greatly reduced from reaching speakers, effectively blocking them.

In technical terms, it’s based on the point at which the output of a crossover has a loss of 3dB. In electrical power terms, the -3dB point is the frequency at which the power to the speaker is reduced by 1/2.

As we get further past the crossover frequency (the -3dB point) the output will decrease more and until it’s essentially zero. For example, for a -6dB/octave tweeter crossover with a cutoff at 1kHz:

  • The tweeter will have a -3dB output at 1kHz.
  • At one octave away (500Hz), the output will be -6dB.
  • At frequencies even further away the output will be nearly 0 decibels.

Choosing your crossover design type and related details

what type of crossover do you need

Choosing a crossover type and slope

Here are some recommendations for the best crossover slope and crossover order types to use based on your speaker system. Note that these are generally the most popular and work for most cases.

  • For a simple tweeter crossover (high pass, for treble or “highs”) or woofer or midrange speaker crossover (to pass a low frequency signal) a 1st order, 6dB/octave type is usually fine. Second order, 12dB/octave designs are optional as well if you want to filter out unwanted frequencies even more sharply.
  • For 2-way speaker systems a 2nd order Linkwitz-Riley is often the best compromise between sound quality and performance. Although 1st order is simple and easier to build it’s not ideal unless you have a specific reason to do so. Another benefit is that they provide an in-phase speaker output when used correctly (I’ll cover this later).
  • For 3-way designs a second order type is fine and also avoids issues with phase problems and other complexities that can come up.

Linkwitz-Riley vs Butterworth and other 2nd order crossover types

Linkwitz-Riley designs are hands-down one of the most commonly used for a number of reasons – the main one being its flat response where the woofer and tweeter crossover point outputs overlap. Other designs like Butterworth, Chebychev, and Bessel don’t offer the same frequency response although they do offer various amounts of gain which can be useful for specific design goals.

The Linkwitz-Riley (L-R) crossover is an excellent choice for building a standard speaker design with its -12dB per octave slope and good (flat) output.

The second-order L-R crossover is an all-pass configuration which sums to a flat magnitude…

The flat magnitude response, low sensitivity to offset, and in-band driver resonances have made the L-R a popular choice among manufacturers.Vance Dickason, The Speaker Design Cookbook (7th ed.)

Although it’s a separate topic, the L-R crossover isn’t sensitive to speaker driver resonance which is another benefit. If you’re interested in learning more I encourage you to get your hands on a copy of Vance Dickason’s The Loudspeaker Design Cookbook.

How to find your crossover frequency values

choosing crossover frequency for 2-way speakers example image

The good news is that there are a few ways to tell what crossover frequency you should pick to design & build your own:

  1. Manufacturer recommendations.
  2. The speaker’s frequency response if that specification is provided. (It’s not always available, unfortunately!)
  3. General rules of thumb based on the type and size of the speakers you have (tweeters vs woofers, small cone vs big cone speakers, etc.).

You’ll probably end up using 2 or more of the things above to get the best results.

Note: I’ll also cover 3-way speakers separately as well since they’re a bit of a special case. See below for that.

1. Manufacturer recommendations

tweeter speaker recommended frequency use example

If you’re fortunate your speaker company may have provided a good frequency range for use. For the example pictured above you’d pick a crossover frequency of at least 3.5kHz which happens to be a very common one.

2. Driver frequency response chart or specifications

example of a tweeter speaker frequency response graph

If you’re lucky enough to have a frequency response graph with the speakers you’d like to use you can see the areas where they have a poor output and use this as a guide. These are the areas you’ll want to avoid.

To do so, pick a crossover frequency away from this range. When using 2 or 3-way setups this should ideally be the point at which the other driver or drivers can produce sound as well. The idea is to find a “middle point” that both can produce sound up to that point without a gap, or significantly weaker, range of output.

From the example above, we can see that the tweeter shown has a good output until somewhere below 2 kiloHertz (2kHz). Knowing that we’ll want to choose a crossover frequency that’s at least 2kHz or higher.

3. Speaker size and type

example speakers using crossover frequencies image

To pick the cutoff needed based on your speaker driver size and type the following rules of thumb are helpful:

  • Tweeters use a small driver that can’t handle bass or midrange in many cases. Most can produce sound from about 3kHz and above, so a 3kHz or 3.5kHz high-pass cutoff frequency is usually a great choice.
  • A midrange speaker used in a 2-way design is usually also good to about 3kHz-3.5kHz. [For a midrange driver in a 3-way design see my notes further below.]
  • Woofers that produce some midbass or midrange frequencies often need a low pass around 120 to 250Hz.
  • Subwoofers do poorly with anything other than a very limited low frequency range so 80-100Hz is often best. 120Hz is applicable in some cases as well.

3-way crossover frequency notes

Although it might not seem like it, 3-way crossovers aren’t just a simple extension of a 2-way design. The idea, in this case, is to use an all pass crossover (APC) design with a large frequency range between the high pass frequency and the low pass frequency.

That’s because undesirable interactions can happen if they’re too close together. You can use my table below or this general rule based on the ratio of the high pass cutoff (Fh) and low pass cutoff (Fl):

Good 3-way crossover ratio: Fh/Fl = 8 or above.

Some great 3-way crossover frequencies to use are:

  • 3kHz/375Hz
  • 5kHz/625Hz
  • 6kHz/750Hz

To use the 1:8 ratio above, pick the upper frequency and divide by 8 to get the 2nd. Likewise, you can pick a lower frequency and multiply by 8 to get a good upper cutoff frequency.

Note that 3-way designs have a midrange output with a higher or lower dB level. In this case, the 3-way design has a 2.45 dB gain compared to the tweeter and woofer outputs which is pretty small.

Generally speaking, the further apart the two crosspoints are, the better the combined response of the drivers will be (three octaves is a good starting point).

Crosspoints closer together than the three-octave ideal will suffer from complicated undesirable interference patterns.Vance Dickason

Designing the crossover circuit and finding part values

designing your crossover section image

Once you’ve got the following:

  • The crossover type you need.
  • The crossover frequencies.
  • Your speakers and their impedance (speaker Ohms rating).

…you can get down to work! The good news is it won’t be very hard – you don’t have to do the math yourself unless you prefer to. You can use my speaker crossover calculator to give you the part values you need.

speaker crossover calculator main image
Speaker Crossover Calculator
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Using a crossover calculator

speaker crossover calculator inputs outputs labeled diagram

It’s fairly self-explanatory but not to worry as I’ve provided instructions on the calculator page. Enter your values and selections for:

  • The crossover type (a diagram will be displayed to clarify it).
  • The speaker impedances used.
  • The crossover frequency/frequencies as needed.

Write down or save the values, either on the schematics below or somewhere else you can find them.

DIAGRAMS – crossover network schematics to print and use

speaker crossover schematic printout PDF image

Click here to view or print the crossover schematics provided for building your DIY crossover. Space is provided on the printout to write down your calculated part values if you like.

Getting your parts together

collecting parts to build speaker crossover

Shopping for crossover components

You’ll need the following types of crossover components at a minimum:

  • Electrolytic non-polarized (bipolar) capacitors with a sufficient voltage rating. This is generally about 48V or higher rated.
  • Air core inductors, although ferrite bobbin (ferrite core) types are fine too but not required.

Capacitors are rated in units called Farad and usually sold in “microFarad”, also sometimes written with the greek symbol Mu (µF, 1/1,000,000 of a Farad) or with a small “u” (uF). Inductors are measured in Henries and usually sold in milliHenries (1/1,000 of a Henry) written as “mH”.

Bipolar versus polarized capacitors

examples of electrolytic capacitors

Polarized capacitors are the most common type but won’t work for audio use – you MUST use non-polarized types. That’s because 1) they can’t handle an alternating current (AC) voltage that reverses and 2) they can distort the sound and even fail. Non-polarized capacitors allow an electrical musical signal to pass fine.

Bipolar (“BP”, non-polarized) capacitors are usually marked as such while polarized types have one side with a stripe marking the negative connection.

Capacitor voltage ratings

Capacitors can’t handle a voltage applied that’s over there maximum rating. 48V or higher is a good rule of thumb although you can calculate the minimum value yourself using Ohm’s law if you know the amp’s RMS power rating like so:

V (volts) = square root(Power x speaker ohms)

For example an amp with 50W per channel to a 8 ohm speaker will have an output voltage of about square root(50 x 8) = 20V. A higher voltage rating would be fine but we don’t want to go below 20V. We’d use the next largest rated part we find or higher.

Part value tolerances (why not to look for “perfect” values)

Electrolytic capacitors and air core inductors have a tolerance of about plus or minus 20% of their labeled value (+/-20%). More expensive parts may have 10% or lower tolerance which is nice but not really necessary.

I say this to help get the point across that:

  • No capacitor or inductor will have a perfect value – they vary slightly from their rated value.
  • You don’t need an exact value, but rather the goal is to get it pretty close to the value you need.
  • Inductors, capacitors, and resistors are sold in standardized values and you’ll almost never find the EXACT value. In many cases it’s not stocked by a supplier and not worth the time trying to search and search for it.

For example, a capacitor labeled as 4.7 uF (4.7 microFarad) may have an actual of around 3.76 to 5.64 uF when measured with test equipment. (It’ll probably be around 4 to 5uF but you see what I mean). The same is true for inductors too.

In that case, you’d buy a 4.7uF one if it’s reasonably easy to get but if not, the good news is there’s another way.

TIP: How to get the part values you need if you can’t find them

how to use multiple capacitors inductors diagram

There’s a simple way to handle not finding the exact part values you need. The trick is to use multiple crossover components in such a way that they add up close to what you’re after.

  • Inductance adds when they’re connected in series and divides when wire in parallel.
  • Capacitance adds (sums) when they’re wired in parallel. The total capacitance divides when connected in series.

This means you can use spare parts or buy other parts of different values that are available to accomplish the same thing!

Miscellaneous parts you’ll need

DIY speaker crossover parts list with examples

I can’t recommend enough being prepared. Here’s a general list of what you’ll need to build and encase your passive speaker crossovers:

  • Project enclosure (if not being mounted directly inside a speaker cabinet), ideally made of ABS plastic.
  • [Optional] Breadboard or other flat material for a mounting surface.
  • Speaker wire or miscellaneous wire for connecting the components to each other and wire terminals.
  • Sandpaper or metal file to remove insulating enamel from inductor wire ends.
  • Wire terminals: I use a dual row inline wire terminal strip as they’re relatively easy to get, not expensive, and can be mounted with screws.
  • Adhesive to mount your parts: General adhesive, silicone-based adhesive, or a hot glue stick and a hot glue gun (although not recommended for hot areas).
  • [Optional] Labels: Clear Scotch tape or shipping tape and white paper + permanent marker or black & white printer.
  • Typical hand tools: cutting pliers or needle nose pliers, Philips screwdriver, and others as needed.
TIP: When shopping for a project enclosure, be aware that the screw thread columns take up some of the internal space. You may need to buy a slightly larger size if the space is too tight.

diagram of typical plastic project enclosure breadboard layout

I recommend always checking how much room you’ll need based on the size of your capacitors and inductors.

DIAGRAM – How to build your speaker crossover

how to build your own speaker crossover diagram

Prepare the crossover circuit & components for assembly

Once you’ve got your parts and the schematic it’s time to jump right in! To build your crossovers, I recommend doing the following:

  • Place the capacitors and inductors in the project box in order to figure out the best placement before you start building. Sometimes space is tight and you don’t want problems when you’re already in the middle of building the crossover network circuitry.
  • If you’re using a mounting board or perfboard, etc., measure between the cover screw columns. This is important because many plastic project enclosures have screw bases that take up space on the inside. Cut your board as needed to fit this area.
  • Although it can be possible to find a single-row wire terminal strip they’re hard to get. I recommend using a dual row strip as they’re affordable and much easier to find.
  • With the top on the box, place the terminal strip slightly below the top to leave enough room for wiring to exit below the cover when it’s on. Using a permanent marker or knife, mark the area above it and cut that section of plastic out.

Mounting & connecting your components

  • I recommend using a non-permanent adhesive like hot glue and a hot glue gun, silicone sealant, contact adhesive, Gorilla Glue, etc. to mount the parts. This way you can remove them later if you need to modify the design or reuse parts.
  • For warmer temperatures hot glue really isn’t so great. Hot glue can become detached from the mounting surface in warm temperatures and doesn’t stick well to smooth surfaces like ABS plastic, either. For that reason I don’t recommend it in most cases.
  • Inductors use magnet type wire which has an enamel insulator you’ll need to remove with coarse sandpaper, a file, or Dremel tool. In order to solder the wire ends, you’ll need to expose the wire surface and provide a good clean contact area.
  • You can use spare speaker wire or miscellaneous stranded hookup wire to connect the components together.

You can also use crimp connectors instead of a soldering iron and solder, although I personally recommend soldering for the best connection possible.

Going by the crossover schematic, connect each section to the next and double-check your work.

Proper placement of inductors

inductor placement example diagram

Inductors, as you may already know, work by increasing the magnetic field strength using loops of wire. Because of this it’s possible for one to cause magnetic coupling (interference) which can induce a signal or distortion in another.

To avoid this, if at all possible mount them at a 90° difference as shown in the diagram above or a minimum of about 3 inches. I begin by placing them at opposite corners of the box when building mine.

Putting it in a project enclosure

Once you’ve got the crossover circuit built, place the whole assembly in the box and use a bit of adhesive to hold it inside if you like (optional). Connect the amp side wiring, negative side wiring, and speaker output wires to the terminal strip on the top row.

This will leave the bottom row free for speaker connections.

Speaker terminals and tweeter polarity

diagram of reversing out of phase speaker on speaker crossover

Second order networks have an output signal phase difference of 180 degrees. Fortunately, unlike odd-order designs (1st order or 3rd order) we can get a perfectly in phase (0° difference) sound output easily.

To do this with second order networks:

  • 2-way speaker systems: reverse the tweeter output crossover connections at the wire terminals and connect the tweeter like you normally would. This puts the tweeter back in phase with the woofer / bass driver.
  • 3-way speaker systems: reverse the midrange polarity to the wire terminals for the crossover.

[Optional] Adding speaker wiring labels

Want to add an extra touch? You can easily make your own labels for your speaker and amplifier input connections. Personally, I recommend the following steps:

  • Using copier or printer paper, write your connection label notes using a Sharpie permanent marker. Optionally you can print using a black and white printer (although it’s harder to get text lined up perfectly).
  • Cut out the labels using scissors.
  • Using clear tape such as large shipping tape, place the tape over the label and trim with scissors if needed.
  • Apply the label to the project box.

Example of a finished DIY speaker crossover

DIY speaker crossover project example image

Here’s an example of my own – one of my first DIY crossovers projects I built myself. As you can see it doesn’t have to be perfect – but does need to be well-connected, use the right parts, and be put together in a way that’s practical for everyday use.

Note that if you’re installing yours directly in a speaker enclosure it’s not necessary to use a project box, but the rest of the steps should still apply.

Hopefully you’ve found my guide helpful. Here’s to enjoying good sound the way you like it – and proving you can do it yourself!

Marty

About the author

Marty is an experienced electrical, electronics, and embedded firmware design engineer passionate about audio and DIY. He worked professionally as an MECP-certified mobile installer for years before moving into the engineering field. Read more »

Your comments are welcome.
  1. I have four small speakers from Paradigm 6.5″woofers and 1″ tweeters that sound great. I have a 12″ powered subwoofer that has the ability to adjust the higher frequency roll off. These are going to be placed in a bar and I want to roll off the bottom frequencies of the 4 speakers at between 80Hz and 100 Hz. This way if they play it a bit too loud the main speakers won’t get destroyed by deep bass going to them and the amp will sort of cruise too. The sub will then get all the deep bass and nothing about that so voices come out of the four speakers along with music and you can’t hear the sub’s location. How do I determine which capacitor to use, handle enough power to not blow out and not degrade the sound of the main speakers? Thank you very much.
    Bob

    Reply
    • Hi there. What you’re describing for the main speakers is essentially having a bandpass filter for the woofers. You can use my speaker crossover calculator, choose the 3-way option, and set the woofer lowpass/midrange highpass to 80-100H as needed. (Enter a dummy Ohms value for the woofer just for the sake of the calculator.)

      Then skip the crossover woofer (low pass) section since you’re using a powered subwoofer. You’ll just need the high-pass and bandpass (“midrange”). Best regards!

      Reply
  2. Hey Marty this is David I’m building a pair of sterling Vega AT-15s which have dual mid-rangers in each cabinet well how would you suggest I run those

    Reply
    • Hi David. Could you be a bit more specific in your question here, “[..] how would you suggest I run those?” I’m not clear on what you’re asking.

      Best regards.

      Reply
  3. Marty, Dave from months ago. I have the 3 way RadioShack speakers with 12 in woofer 8 in mid and Morel Cat 378 tweeter. I finally placed a 2nd order crossover for the Morel. It has a 2/14 port front. Currently the woofer is full range 50-11000hz, tweeter 1800-22000Hz and the Midrange (only infor Fs 100Hz. The woofer has no crossover, the mid has a 20uf 1st order polycap and then the tweeter as above. I was considering the mid placing a second order crossover ( then reverse polarity on it) but did not know how to determine the crossover w/o special equipment. The tweeter 2nd order is listed as 2000hz 5uf Dayton cap and a 2.27 mH inductor. any thoughts ideas or do I just leave the mid with a 1st order crossover. Thanks for your time

    Reply
    • Hi Dave. I suppose we’ll have to somewhat assume a few things about the midrange because of not having more information about it. Using the 1/8 rule for a 3-way crossover, 2KHz * 1/8 = 250Hz for the lower cutoff frequency. However that seems pretty low for a midrange.

      If you were to use 3.2KHz, 400Hz that would be pretty reasonable to use as a guideline. Or even 4KHz, 500Hz if you want to “play it safe” for the midrange’s lower range. You could roughly find out the midrange’s frequency response with a decent microphone and RTA application, but if you don’t have access to that, yeah I’d use conservative numbers like those I listed above (or somewhere in that ballpark, basically).

      I would definitely not just leave the midrange with only the 1st order, assuming you mean it’s a high-pass. You’d definitely want a bandpass (even better, a 2nd order) to keep it from trying to produce bass in the woofer’s range treble in the tweeter’s range. I think it’ll sound a bit poor and/or harsh, otherwise.

      Hopefully that helps.

      Reply
      • Yes , Marty this has a single 20uf high pass filter in parallel on the + line side of the terminal to the midrange. Thank you for the help. Also should I then reverse polarity of the 2nd order crossover to the midrange once I build it. Dave

        Reply
        • Hi, yes I’d remove the 20µF component as needed, or you could just jumper around it to get the same thing, so it doesn’t affect the crossover you end up using. And then reverse the leads to the midrange (assuming it’s not already done in the crossover for you).

          Best regards.

          Reply
  4. Marty, just needed to touch base with you. I am not sure you received my info on the pre-made midrange band pass crossover. It looked like the inductor and capacitor were reversed with the HPF showing cap in series and inductor parallel and the LPF capacitor parallel and inductor series. So if I make my own should I use the schematics of capacitor in parallel on the hpf and inductor in series and the same for the LPF. wiring them cap to inductor HPF then cap to inductor LPF and finally reverse the polarity to the mid range speaker. Thanks

    Reply
    • Hi Dave, yes an in fact wrote you back 3 days ago so you should have received my email unless it went to spam or some possible odd thing (?). I resent it in case so please check it as I think it will answer much of your question(s).

      For a high pass, you use a series capacitor, parallel inductor. A low pass is the opposite. For the band pass there’s more than one way (see my email). Best regards.

      Reply
  5. Hello Marty, very helpful information discussed. I want to build a passive crossover for a 4ohm 18 inch single subwoofer, lowpassed at 100hz, that will be getting abused with about 1000 watts. I need help on how to connect the passive crossover to the subwoofer. Do I just connect the speaker wire to the inductor and then to the subwoofer? Do I need to make a whole board as mentioned above? Do I need more than just and inductor? I would really appreciate the help that I need.

    Sorry to add on but I also need help on what exact parts I need.

    Reply
    • Hello Robert. To find the parts values, use the crossover calculator you can find at the link in this article.

      An inductor will be fine for a -6dB/octave crossover, but they’re not great for woofers etc. a -12dB/octave crossover (2nd order) would be better. That would be an inductor in series and a capacitor in parallel. Generally you just connect the inductor inline with the positive speaker wire, yes, or you can do it right at the speaker also.

      However, a 1,000W RMS inductor will likely need to be made of a fairly large conductor (1,000W RMS is about 15 amps at full power) and that won’t be so easy to find. Large inductors for low crossover frequencies with a high power rating may be tought to get.

      You’d be better off using an electronic low-pass filter in this case if possible. Best regards!

      Reply
      • Thank you for taking time out of your day to respond to my questions. This helped. I will go for the electronic low-pass filter.

        Reply
  6. Hi, Marty,
    Good day! I have enjoyed reading your article–very informative and easy to understand. Thanks a lot!
    The motherboard on my PA system had ceased to function with an unacceptable repair cost, so I thought I’d just keep the speakers with the baffle but do not know what ratings (voltage included) of the capacitors and coils to use for crossover. I cannot simply pull out the parts from the motherboard as they are integrated with the amp and with very different values from the results of the calculation using your formula.
    It consists of a tweeter (6.3 ohms) and 3 woofers (8.3 ohms individually). Here’s what the manufacturer says,
    “Trouper is a 2-way 200-watt bi-amplified system (130 watts LF/70 watts HF) with (3) 6 ½” (165mm) woofers and a 1” (25mm) high-frequency compression driver, spanning the full musical frequency range from 65-20kHz. The system has thermal and dynamic overload protection, so the sound is always clean and clear no matter how hard you push it.”

    I would really appreciate if you could give an advice on the best crossover circuit for it.
    Thanks in advance and more power to you.
    -Audie

    Reply
    • Hello there Audie. So to be clear, I assume you got the 6.3 Ohm value for the tweeters by measuring them with a test meter (Ohms range)? If so, that’s not their impedance but rather just the DC resistance (DCR). Is there an Ohms rating for them? As they’d often be 8Ω.

      Regarding the crossover(s), you can find the minimum voltage rating for the capacitors using the power formula: P = V^2 / R. If you know the maximum power you’ll be powering them with, you can find the RMS voltage this way:

      V = Square_root(P x R) , where R = the speaker impedance. Then use the voltage rating as a *minimum* guidline when buying capacitors. For inductors, they are typically rated for a certain power, but actually it’s about the current they can handle.

      Using the power & current formula P = I^2 x R, You can find the current at maximum power by: I (amperes) = Square_root(P / R). That way you’ll know the max. rating you’ll need (if required) when buying inductors.*

      Here are some example values:
      • V @ 200W RMS, 8Ω: SQRT(200×8) = 40V
      • I @ 200W RMS, 8Ω: SQRT(200/8) = 5A

      Regarding the general design, I wouldn’t use less than a 2nd order crossover, and a Linkwitz-Riley design should do great. If you don’t know the tweeter’s frequency range, 3.5KHz or 4KHz as a crossover frequency are generally pretty good bets.

      Hopefully that helps! :)

      Reply
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