Ready to design and build your own speaker crossover? You’re in the right place!
Here’s a very easy-to-use speaker crossover calculator along with great info to help you.
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Contents
SPEAKER CROSSOVER CALCULATOR
You can use my speaker crossover calculator to generate parts values to build your own capacitor, experiment with different values, and more.
How to use the calculator
- Select the crossover type:
- 4 types are available: 2-way 2nd order Linkwitz-Riley (12dB/octave), high or low-pass 1st order Butterworth (6dB/octave), 1st order 2-way Butterworth (6dB/oct.), and 1st & 2nd order 3-way crossovers.
- A speaker crossover schematic matching the type you chose will be shown.
- Enter the speaker impedance (Ohms) as needed. This can be whole numbers, fractions, or both. (Ex.: 4 ohms, 3.6 ohms, etc.)
- Enter the crossover frequency desired. For 3-way crossovers, enter the bandpass upper (tweeter/midrange) and lower (midrange/woofer) cutoff frequencies. (*See my notes below regarding 3-way crossovers below.)
The calculator will output capacitor and inductor part values as needed. Parts are labeled to match the the example schematic shown for each type you select.
Reversing out of phase speakers for even-order designs
When building a speaker crossover and using a 2nd order or other even-order designs, it’s important to remember to reverse one speaker driver to correct the 180 degree out of phase condition.
Crossover capacitors and inductors each add a 90° phase difference, giving 2nd order crossovers a 180° out of phase condition that will affect the sound.
An out of phase condition can result in destructive interference (sound wave cancellation) in the overlapping range of sound between two speakers (three speakers in the case of a 3-way system) near the crossover frequency. It will also sound “weird” because the timing of the audio waves you hear conflicts.
For example, you can hear the same effect if two speakers are placed near each other with one having its speaker wiring reversed. In that case, you may notice poor bass until one speaker is disconnected due to cancellation.
Image showing 180 degree out of phase audio waves and the resulting in-phase (0° difference) condition after reversing the speaker.
Fortunately, there’s an easy fix:
- For 2-way crossovers, reverse the tweeter connection polarity.
- For 3-way crossovers, reverse the bandpass speaker (midrange speaker) polarity.
You can do this by reversing the wiring at the speaker terminals in the crossover building stage or reversing the connection polarity label once it’s completed.
This is almost never a problem for ready-made crossovers you buy as this is usually already taken into account when they’re designed.
Why use a Linkwitz-Riley crossover for 2-way crossovers?
Linkwitz-Riley designs are hands-down one of the most commonly used for a number of reasons, one of which is their flat response where the woofer and tweeter crossover points overlap. While it’s true that plenty of other designs exist (Butterworth, Chebychev, Bessel, and others) they do not offer the same frequency response.
They certainly have useful applications but the Linkwitz-Riley (L-R) crossover is generally a great choice for standard speaker systems with a -12dB per octave slope.
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 Loudspeaker Design Cookbook (7th ed.)
It’s also not sensitive to speaker driver resonance like some others. If you’re interested in the technical aspects of the different crossover designs available, I’d encourage you to read more.
I highly recommend Vance Dickason’s The Loudspeaker Design Cookbook for more detailed information as it shows examples and covers the topic in good detail. You’ll also learn tons of other speaker design info!
3-way crossover details for the calculator
To get the best results (3-way crossovers are NOT simply an extension of 2-way designs), the calculator uses a 3-way all pass crossover (APC) design with a sufficient frequency range between the high pass frequency and the low pass frequency.
You can also use a general rule based on the ratio of the high pass cutoff (Fh) and low pass cutoff (Fl):
Some great example 3 way frequencies to use are:
- 3kHz/375Hz
- 5kHz/625Hz
- 6kHz/750Hz
Or, simply 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 frequency.
However, do be aware that 3-way designs have a midrange output with a higher or lower dB level – in this case, the 3-way design provided has a 2.45 dB gain vs the tweeter and woofer. (This is a pretty minor difference however)
Crosspoints closer together than the three-octave ideal will suffer from complicated undesirable interference patterns.Vance Dickason
Consider adding a Zobel network and series notch filter
Want even better results from your speaker system? Consider adding a Zobel impedance compensation network and in the case of midrange & tweeter drivers a series notch filter. Those will tame nasty impedance issues:
- The steep impedance rise at higher frequencies due to voice coil inductance.
- Very high (peak) Ohms at the resonant frequency “Fs.”
I cover all this on my Zobel network and series notch filter calculator page.
How precise do crossover capacitor and inductor part values need to be?
I recommend trying to get fairly close to the calculated parts values; exact values are not practical or needed. For example, if the calculator recommends a 10.56mH (milliHenry) inductor, you’d try to get close to 10.5 mH, not 10.56mH. If you found a 10.2mH for example, that would usually be close enough.
Similarly, for the parts themselves, standard tolerance parts are fine for most designs. You don’t need to spend additional money on better tolerance components.
Of course, that doesn’t mean you shouldn’t use better quality or higher performance parts if you’d like – just that for most cases standard (20% – 15% tolerance) is fine.
Typical inductor and capacitor tolerances
The truth is that picking super-precise part values is kind of useless anyway because the components have as much as a 20% tolerance. For example, a 4.7 µF (4.7 microFarad) non-polarized capacitor, 20% tolerance, could have an actual capacitance as low or high as:
- Low end: 3.76 µf
- High end: 5.64 µF
As you can see, trying to pick the perfect parts values doesn’t make sense because they won’t be exactly that value anyway. That’s out of your control. Just try to get it pretty close if possible.
Most inductors are similar as well – especially air core wire wound inductors.
Affordable ways to get better sound performance
Electrolytic capacitors are extremely common in speaker crossovers and filters..but did you know? There’s another little-known way to get better sound and better parts quality without spending a lot: polypropylene, polyester, and film capacitors.
They offer some nice benefits for only a little bit more money:
- Longer life/don’t leak over time like electrolytic capacitors
- Higher voltage handling (great for vacuum tube designs!)
- Better audio performance (better for carrying the audio signal)
- Vertical solder leads may make them easier to use in printed circuit boards or DIY projects
- Some film capacitors are more compact than their counterparts
Film capacitors are generally bipolar (non-polarized) so they’re great for audio designs, but it’s important to always check the specs to be sure.
Also, be sure to verify their voltage rating – you’ll want a rating that’s at least equal to or higher than your amp or stereo’s output voltage generally.
Inductor options
They’re not mandatory, but you can also consider using iron core or metal-core inductors. These types have a more dense magnetic field characteristic, meaning they can be a bit smaller than air core models in some cases.
What voltage audio capacitors do I need?
There’s an easy way to find the voltage rating for audio capacitors in crossovers: you can find the approximate stereo amplifier or radio output voltage if you know the power per channel (RMS or continuous) and speaker Ohms.
Simply use this formula: Volts = square root(Speaker Ohms x Max. Continuous/RMS Power)
This will give you the approximate voltage at maximum output power. Once you know that, I recommend using capacitors with a voltage rating at least the same, if not higher, voltage rating.
Otherwise, for standard power levels (not using maximum power out), you can use the next closest value.
Off-the-shelf bipolar capacitors sold for audio applications are normally of a sufficient working voltage. Still, it pays to check. Lower voltage bipolar parts (5V, 16V, etc.) are usually used for low-voltage (line level) electronics.
TIP: adjusting the crossover frequency to match parts on hand
Here’s a helpful tip I’ve picked up after building my own crossovers. If you’ve got parts on hand you’d like to use you might be able to do so by slightly changing the crossover frequency.
For example, let’s say you use the calculator for a 2-way 2nd order design at 3,000Hz, 4Ω:
- C1, C2 = 6.63uF
- L1, L2 = 0.42mH
Let’s also say you have some capacitors on hand that are below 6uF. By changing the crossover frequency slightly, you can sometimes use parts you already have.
Obviously this won’t always work, and not all speakers are suited for it, but it’s a helpful strategy in some cases. Using a calculator, you can play around with values in seconds and see what works.
Hello Marty, I read that you recommend reversing the polarity on the midrange when designing a 3-way system. Should that always be the case? I’ve never heard that, and with the speakers I’ve built in the past, I never noticed anything unusual with the sound. This concerns me about my ability to decipher sound waves. Thank you for mentioning that.
With that said, I’m in the process of design/build of two completely different Open Baffle systems: a 4-way and a 3-way. How would I set the polarity for the 4-way?
1. GRS 12PT 8-ohm, 93dB – 12″
2. Dayton MB620-8ohm, 94dB – 6.5″
3. Dynaudio D-54 – 8ohm, 96dB – 2.2″ dome
4. Dynaudio D-28 – 8ohm, 93dB – 1″ dome
Now, in the early 80s, I used these (2) drivers in a number of systems. Dynaudio developed a system they called “aperiodically,” which they promoted heavily at the time. I’m not sure if you’ve heard of this method. However, they would pack the damping material in tightly to give the speaker the impression that they were in a larger box. This is how Dynaudio kept their box sizes down. It also had a significant impact on the woofer’s attack time, providing higher headroom for a more powerful dynamic impact.
The mid-ranges and tweeters are designed according to this idea; hence, they are housed in their own enclosures and packed with damping material.
However, let me introduce you to a problem that I inherited this morning. I planned the crossover between the woofer and the mid-bass to be either 400Hz or 500Hz, until I came across the fact that the male voice is between 85Hz and 180Hz. I didn’t want the woofer to carry any voices, and it doesn’t make sense to drop the woofer crossover that low, since I will be incorporating a Klicsph Bash subwoofer to pick up the bottom end. I wasn’t expecting the GRS 12PT to carry the frequency below 45Hz at -3dB. I did some calculations, and at a 3.54 CF ported box, it’ll hit 36Hz at -2.77dB. But that is a big box, plus I am going free-air. However, I will be building an open-ended box for the woofer, not a sealed one, which will probably raise the bottom roll-off even higher.
Okay, this now bothers me. Any recommendation? And if I did stay with the 4-way, where am I with the polarization? And another question: Can you recommend a source for purchasing inductors and capacitors at a reasonable cost? I cannot believe how much these items have jumped in price. And the D-54 I bought in ’83 was priced at around $40-$45. I just saw it for sale at $343. The D-28 I could buy in the low $30 range, which I thought was really costly since I could buy a Peerless HD 9×8 D 25 for around $12.
Thank you, Marty, in advance for your help!
Here there Simon. I’ll post your questions one at a time below so I don’t lose track.
> I read that you recommend reversing the polarity on the midrange when designing a 3-way system. Should that always be the case?
It’s recommended in two cases: 3-way 2nd order crossovers (for the midrange) and 2-way 2nd order systems (typically done on the tweeter output by convention). You don’t usually need to do so for 1st order & 3rd order crossovers because the speaker phases aren’t 180° unlike a 2nd order.
It’s often mentioned in speaker/crossover design books but for some reason it may not be mentioned elsewhere.
You won’t always notice it, particularly in a 3-way design, but it definitely can make a difference as a 180° reversed speaker will cause cancellation over some frequencies or can sound “off.” It also depends on the musical content frequencies being produced.
If you were to do an A/B test of one reversed and one not reversed it would likely be easier to hear the difference. It’s not mandatory but recommended so it’s best to try and see what you get.
> How would I set the polarity for the 4-way?
It depends on the order (1st order, 2nd order, etc.) type of design you’re planning to use. If it is a 2nd order design you’d reverse each 2nd speaker (that is, #1 & #3 remain the same while #2 & #4 are reversed.) But again changing the polarity isn’t mandatory, more like a “this is often better but it depends” type of change.
But honestly with a more complex design like 4-way trial and error listening is probably the best way to start (unless you have audio test devices to check the speaker output).
If you use an audio measurement application& microphone you can see dips around the crossover points depending on how the speaker is wired (reversed or not). You may not need to bother with reversing them.
> I didn’t want the woofer to carry any voices
Is there a particular reason for this? Generally we use woofers for this range since (for one reason) midrange often don’t have adequate output that low.
I’m not 100% clear on what setup you had in mind since you mentioned both 3-way and 4-way in your comment. What range would you like to use which woofer for? It sounds like you should leave the woofer covering the midbass range, or give up one speaker to allow one best suited to cover the woofer-midbass range of frequencies. But I’m not clear on your idea exactly.
> Can you recommend a source for purchasing inductors and capacitors at a reasonable cost?
I still rely on Parts Express but unfortunately there aren’t many options out there. Sometimes however I’ve found some parts on eBay as well (especially power resistors – particularly in packs of 4-5).
For fancier designs I got film/polyester non-polarized capacitors (Ex: “Orange Drop” type) from Mouser, Digi-Key, and also eBay.
It’s a bit hard to find parts unfortunately and I know what you mean about inductor cost.
One thing to consider is perhaps sticking with a traditional 2-way or 3-way design as you can rely on established formulas & examples to get what you’re after. I hope this helps some!
Best regards.
Hi Marty! I just now saw your response. I am very sorry for not getting back to you sooner. I never received an email back. I guess that doesn’t happen? However, thank you for your response; your instruction was invaluable indeed.
About the woofer not carrying male voices. It’s in the 4-way I was talking about. I’m employing the GRS 12PT – 12″ up to about 80 or 100Hz, with the Dayton MB620 – 6.5″- covering the midbass. I’m building an open-baffle 4-way, but using an actual woofer enclosure with the GRS to bring a lower bottom end since the QTS is too low for the driver in an open-baffle application. I’m ready to test the 2.25 f3 enclouser with a ported, sealed, or open-box end to see which works best.
The Dayton MB620 has a nice frequency line down to 100Hz, which I thought would make a good crossover point. Hoping it would work better for male voices, given its smaller, lighter, and tighter cone. I’m looking at putting a Dynaudio D-52 midrange and a Goldwood Sound GT-525 front- and rear-firing tweeters. This is why I asked you about reversing the positive feed.
I have another question: let’s say the crossover point for the woofer is at 100 Hz with an impedance of 12 Ohms. Would I not design the network at 12 Ohms, not 8? Or should I bring the Ohms down? This would lower the driver’s SPL, correct?
I’ve been watching GR Research on designing an open-baffle system and going to give some of his suggestions a try.
Another question. I want to purchase an integrated 2.1 amp/ 100 WPC for under $400. Any suggestions? I have been scouring YouTube, eBay, and the like. I keep getting hit with these mini D chifi amps, but I don’t see them as having much of a headroom for impact. So far, none of the reviews have mentioned this, except Wilson Audio. I need high punch power since I’ll be using a ribbed surround rather than a rolled one. Bad idea? The roll surround drivers can be muddy at times and have slower attack times. Does this make sense to you?
Have you tried Madisound.com for drivers or network components? They have a great closeout, buyout, and clearance sale.
Thank you for all your help, really, thanks!!
Hi Simon. No problem taking your time.
Ah ok, I understand a bit better what you’re working on with your additional details you put here.
> I have another question: let’s say the crossover point for the woofer is at 100 Hz with an impedance of 12 Ohms. Would I not design the network at 12 Ohms, not 8? Or should I bring the Ohms down? This would lower the driver’s SPL, correct?
If it’s a hypothetical question where you’re using a 12 Ohm speaker, yes ideally you would design the crossover for the 12 Ohm load. You *can* use an 8 Ohm rated crossover and bring the total Ohms load down to 8, but that means some power will be wasted across the power resistor used for that.
If we simply add resistance (24 Ohms) in parallel with the 12 speaker to bring the total down from 12 Ohms to 8, the speaker’s dB output wouldn’t change as long as we don’t add a series resistor to it.
Some power will be wasted as heat across the resistor(s) we add.
> I want to purchase an integrated 2.1 amp/ 100 WPC for under $400. Any suggestions?
Unfortunately I don’t have a good recommenation as for some reason that seems to be hard to find (2.1 channel amps with decent power & quality). You might be better off with a 2 channel amp + plate amp for the subwoofer. But they usually have a low-pass crossover built-in also.
> Bad idea? The roll surround drivers can be muddy at times and have slower attack times. Does this make sense to you?
Hmm, I would have to read more about this as I’m not familar with that. For some reason I haven’t heard of this before. I wouldn’t think the surround would affect performance that much but I can see how it may make a difference.
I did browse Madison.com a bit in the past, so I’ll check it out again. Thanks for the reminder. :)
If you like it may be easier to email me directly in the future at marty [at] soundcertified.com.
Best regards!
Hi Marty, thank you for your direct connect and thank you for a “wow fast” response! I’ll connect with you there about the resistors in series as Parts-express advised me to do.
Thanks!
I’m building a 2-way speaker with a JBL 12PW5 woofer and JBL D220Ti driver and I’d like to know what the best cut would be to have maximum quality for residential hifi use.
Hello, Marcio! I looked over the specifications and here are my suggestions:
Have a good day.
Thanks for taking the trouble to offer so much information. The calculator is good. I do wish and hope that you come up with an online calculator that can help ignorant people like me simply get to know the diameter of the coil, swg of the wire, and the number of turns, in order to arrive at the calculated mH value. For example, if I pick a 25mm air core diameter for the coil and, say, 50mm length, and choose to use 18swg enamelled copper wire, I should be able to know the number of turns required to get the required mH value for a desired crossover frequency.
Hi Sashi. That’s an interesting idea for a calculator and I can add it to my “to do” list as I have a few other ideas, too. Some of which will require more advanced coding skills but I’m currently studying those.
If you need a calculator for building your own inductors sooner, I’m sure there are some out there on the web. Thanks for visiting my site!