I have read information for some time now, including topics on this forum. But I haven't found an answer yet. I want to use a set of 4 ohm tweeters in my car, high passing at 3500hz with at least 12db. I have looked at a Linkwitz Reilly crossover design and I got values of 5,69uF and 0,36mH. Here's the thing though. It's a budget build and the inductors I have found and are not said to be of mediocre quality (vented core copper for example) cost a lot of money. If need be for good quality sound then I will pay the money. But I was wondering if anyone has any knowledge how I could do this cheaper without much quality loss? I'm hoping not having to spend 30 to 40 dollars on a set of 2nd order high pass filters.
This will not be a Linkwitz Riler crossover. It could be for a 4 ohm resistor, but not for a real speaker with uneven response and impedance. This could be a more important issue than the one you mention.
You will have used a simple crossover calculator.
However, the tweeter is unlikely to have an exact impedance of 4 ohm at 3.5 kHz (because impedance increases with frequency), meaning that a simple calculator does not produce the optimum component values to suit your particular tweeter.
However, the calculated values are better than nothing, and may have to suffice if you do not have the facilities required for testing/software modelling.
Importantly, using the calculated values will not harm your tweeters!
P.S. A 2nd order Butterworth crossover calculates as 8 uF, 0.25 mH and I'd settle for that.
Look for audio air core inductors like these: https://willys-hifi.com/collections...ctors-air-core-1mm-ofc?variant=33569754480699
Simply choose the available standard value nearest to the theoretical value indicated by the calculator.
However, the tweeter is unlikely to have an exact impedance of 4 ohm at 3.5 kHz (because impedance increases with frequency), meaning that a simple calculator does not produce the optimum component values to suit your particular tweeter.
However, the calculated values are better than nothing, and may have to suffice if you do not have the facilities required for testing/software modelling.
Importantly, using the calculated values will not harm your tweeters!
P.S. A 2nd order Butterworth crossover calculates as 8 uF, 0.25 mH and I'd settle for that.
Look for audio air core inductors like these: https://willys-hifi.com/collections...ctors-air-core-1mm-ofc?variant=33569754480699
Simply choose the available standard value nearest to the theoretical value indicated by the calculator.
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Thanks for your comment Galu.
I'm back with more knowledge. I have read a few articles, mostly from Audioholics. I now understand the following:
So personally I think that my original plan, given the current situatuin and perhaps with different values for the components as suggested, will still give me better sound. But the more data I can measure or receive the better I can design a crossover that fits my situation. I understand why I came with different values than Galu, I now noticed the calculator was configured to calculated the crossover frequencuy as f6, not f3. Chaning to f3 gives me the same values (http://mh-audio.nl/Calculators/CBBC.html).
My questions for now:
Thanks for your input!
I'm back with more knowledge. I have read a few articles, mostly from Audioholics. I now understand the following:
- Ideally one has the actual frequency curve from the driver in half space measurement.
- Same goes for impedance frequency.
- Resistors can be used to get efficiency at the same level for a more flat compound frequency curve.
- Inductors and capacitors can be used for correcting Irregularities in both curves.
- Air cores are best quality wise and preferred where size and costs do not become too impractical.
- Capacitors should me used of the film type.
So personally I think that my original plan, given the current situatuin and perhaps with different values for the components as suggested, will still give me better sound. But the more data I can measure or receive the better I can design a crossover that fits my situation. I understand why I came with different values than Galu, I now noticed the calculator was configured to calculated the crossover frequencuy as f6, not f3. Chaning to f3 gives me the same values (http://mh-audio.nl/Calculators/CBBC.html).
My questions for now:
- Are there things I can easily measure myself that are relevant for what I want?
- Is there a guestimate for what the impedance at 3500hz could be roughly?
Thanks for your input!
Nice bit of research, Sjakkie, well summarised!
You could research further on methods of measuring loudspeaker impedance versus frequency, but my opinion is that this is unnecessary given the simple application you have in mind.
As for a "guestimate", you could look at the 4 ohm tweeter impedance curves that are published by the major manufacturers.
You could research further on methods of measuring loudspeaker impedance versus frequency, but my opinion is that this is unnecessary given the simple application you have in mind.
As for a "guestimate", you could look at the 4 ohm tweeter impedance curves that are published by the major manufacturers.
This may help reassure you:
The impedance curve (bottom trace) for a Monacor DT-284 dome tweeter (intended for car Hi-Fi applications) shows that its impedance departs little from its nominal impedance of 4 ohm at frequencies above its resonant frequency of 1,300 Hz.
https://www.monacor.com/products/pa...y-and-speaker-building/hi-fi-tweeters/dt-284/
The impedance curve (bottom trace) for a Monacor DT-284 dome tweeter (intended for car Hi-Fi applications) shows that its impedance departs little from its nominal impedance of 4 ohm at frequencies above its resonant frequency of 1,300 Hz.
https://www.monacor.com/products/pa...y-and-speaker-building/hi-fi-tweeters/dt-284/
Details of the Hertz HT 25 tweeter are included in the specification page (24) of this manual:
https://www.manualslib.com/manual/625613/Hertz-Ht-20.html?page=24#manual
Maybe you are interested on some real world experience from decades of car HIFI?
To begin with what Galu suggested is very promising. Pick these values for a start. Install your tweeters in the car and pick a CD for critical listening. Put all sound controll and enhancers to neutral. If you don't want to measure, you can try tuning by ear.
What you have to know, the placement of a tweeter in a car completely changes any frequency response. So moving from the door to the dash makes any prior tune invalid. Some cry badly about the impossible acoustical situation and bash any car HIFI, others, like me, simply accept it and try to make the best they can from it. The windschield is a hard reflector, I try to see it as an advantage to get some pleasing, interesting sound effect.
This is nothing to be compared to high end home HIFI, just a very own way of listenig experience. Like Stereo compared to headphones and 7.4.2 surround sound. Different game. You should tune in a way that makes it pleasant to listen to music and voices while driving.
The first thing when you start listening, expect the tweeter to be too much for the (door) speakers they assist. So you need some resistors. 2 Watt is enough for usual car HIFI. Values may be 2, 4, 6, 8 and 10 Ohms for a start, at least 4 of each value. Don't buy audiophile parts, just good industrial quality. Most of "special audio" caps, coils and resistors simply have fancy labels, but are standard parts underneath. Capacitors in MKT, maybe MKP 100V are just fine.
Coils for the high path need not be lowest Ohm, even up to 2 Ohm are OK. Which means cheap. You need to have some wires with crocodile clips or aligator clamps. Remember, you do stereo. In the end you need parts for two crossovers.
Ok, now take two 4 Ohm resistors, on in line with the tweeter, one in parallel. This will make it sound less loud and agressive. Listen a little while, as your hearing has to adapt to the new situation. Now you know how to change volume in a passive x-over. Read about voltage divider.
Once you found a good combination, take out the coil from your basic capacitor/ coil combination. You will notice the difference in lower highs. You can try larger and smaller coils. Next make the capacitor smaller. Smaller is no problem, just don't use too large value, as it might burn the tweeter. Smaller reduces load on the tweeter and makes x-over frequncy higher.
So you have resistors to change the overall amount of high frequency.
Coils to bend the curve.
Caps to change the x-over frequency.
These all interact with each other.
No one can predict the combination of resistors, coil and cap for your individual installation. I did not even touch the passive ways how to influence dips and spikes in the frequncy curve...
I often have spend a whole day or more on tuning a passive car stereo setup. You still got to have an idea what can be achieved with your components and the installation in the car. Better parts often mean less problems. Often you find resonating body parts or other problems in the process. Very time consuming...
If you find this to complicated, get a measuring microphone and a program like REW. You need a way of injecting the measuring signal into the car stereo. Can be by Aux, a CD or some USB device. This will show you in a second how your frequncy curve looks like, what your change of parts does and reduce the time you need to a fraction of the "ear tune". Still you need to know how the "right" curve in a car should look. Read...
Now you should think the whole plan over. If not:
I suggest to go 2 or (better) 3-way acticve if possible & measure.
For a beginner, this will be the best way to a nice result. If you can change the head unit, there are very good, modern versions with integrated x-over. For less than 200$/€ new. Look Pioneer, JVC, Alpine etc. This is about what a basic set of passive x-over components will cost.
You can even use the internal amps for tweeter and mid speaker, just like external amps. Most have equalizer functions, which are of great help. With active x-over, the impedance problem is erased, by the way. Good used car HIFI components are quite cheap, even new stuff today is high quality for reasonable money. In the end all your invested money will be used, instead of having a heap of unused, expensive parts (coils, caps, resistors).
Good luck!
To begin with what Galu suggested is very promising. Pick these values for a start. Install your tweeters in the car and pick a CD for critical listening. Put all sound controll and enhancers to neutral. If you don't want to measure, you can try tuning by ear.
What you have to know, the placement of a tweeter in a car completely changes any frequency response. So moving from the door to the dash makes any prior tune invalid. Some cry badly about the impossible acoustical situation and bash any car HIFI, others, like me, simply accept it and try to make the best they can from it. The windschield is a hard reflector, I try to see it as an advantage to get some pleasing, interesting sound effect.
This is nothing to be compared to high end home HIFI, just a very own way of listenig experience. Like Stereo compared to headphones and 7.4.2 surround sound. Different game. You should tune in a way that makes it pleasant to listen to music and voices while driving.
The first thing when you start listening, expect the tweeter to be too much for the (door) speakers they assist. So you need some resistors. 2 Watt is enough for usual car HIFI. Values may be 2, 4, 6, 8 and 10 Ohms for a start, at least 4 of each value. Don't buy audiophile parts, just good industrial quality. Most of "special audio" caps, coils and resistors simply have fancy labels, but are standard parts underneath. Capacitors in MKT, maybe MKP 100V are just fine.
Coils for the high path need not be lowest Ohm, even up to 2 Ohm are OK. Which means cheap. You need to have some wires with crocodile clips or aligator clamps. Remember, you do stereo. In the end you need parts for two crossovers.
Ok, now take two 4 Ohm resistors, on in line with the tweeter, one in parallel. This will make it sound less loud and agressive. Listen a little while, as your hearing has to adapt to the new situation. Now you know how to change volume in a passive x-over. Read about voltage divider.
Once you found a good combination, take out the coil from your basic capacitor/ coil combination. You will notice the difference in lower highs. You can try larger and smaller coils. Next make the capacitor smaller. Smaller is no problem, just don't use too large value, as it might burn the tweeter. Smaller reduces load on the tweeter and makes x-over frequncy higher.
So you have resistors to change the overall amount of high frequency.
Coils to bend the curve.
Caps to change the x-over frequency.
These all interact with each other.
No one can predict the combination of resistors, coil and cap for your individual installation. I did not even touch the passive ways how to influence dips and spikes in the frequncy curve...
I often have spend a whole day or more on tuning a passive car stereo setup. You still got to have an idea what can be achieved with your components and the installation in the car. Better parts often mean less problems. Often you find resonating body parts or other problems in the process. Very time consuming...
If you find this to complicated, get a measuring microphone and a program like REW. You need a way of injecting the measuring signal into the car stereo. Can be by Aux, a CD or some USB device. This will show you in a second how your frequncy curve looks like, what your change of parts does and reduce the time you need to a fraction of the "ear tune". Still you need to know how the "right" curve in a car should look. Read...
Now you should think the whole plan over. If not:
I suggest to go 2 or (better) 3-way acticve if possible & measure.
For a beginner, this will be the best way to a nice result. If you can change the head unit, there are very good, modern versions with integrated x-over. For less than 200$/€ new. Look Pioneer, JVC, Alpine etc. This is about what a basic set of passive x-over components will cost.
You can even use the internal amps for tweeter and mid speaker, just like external amps. Most have equalizer functions, which are of great help. With active x-over, the impedance problem is erased, by the way. Good used car HIFI components are quite cheap, even new stuff today is high quality for reasonable money. In the end all your invested money will be used, instead of having a heap of unused, expensive parts (coils, caps, resistors).
Good luck!
A comprehensive guide, Turbowatch2!
You bring up the important point that the tweeter, if too loud, may need to be attenuated.
This can be done, as you suggest, with a form of voltage divider called an L pad, which consists of two carefully calculated resistors, one in series with the tweeter (R1), followed by one in parallel with the tweeter (R2).
Full details, plus a handy calculator can be found here: https://soundcertified.com/l-pad-calculator/
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I had an '85 Saab 900 with upward facing 3.5 inch in the dash and then added tweeters in the doors experimentally. L & R tweeters needed to be different....
Glad I outgrew that!
If you accept Car HIFI as a different sound experience to Stereo and high end, it can be very pleasing to listen to music inside a car. I know there are many that straight reject it.
The majority of car owners do not know how good DIYS car HIFI can be. The DSP today makes results possible that are better than most of the ridiculous expensive build in “sound systems”. If the DAB+ radio stations feed the right data rate, even radio has an incredible good reproduction.
The end result of a today's a 300€ car head unit is comparable to most expensive gear a decade or two ago.
This positive on the hardware side maybe a result of the car industries furious attempts to make retrofitting impossible. In fact, with new cars, you loose the guarantee you desperately need for this driving beta test unit you just bought, if you are so brazen to fit some new speakers or amps.
The legal risk for professional car HIFI fitters is not bearable any more. So most have closed down, know how is lost and a whole form of modern art vanished.
Anyway, if you have a used car you are technically responsible for, it never has been so cheap to get incredible mobile sound. Too bad no ones knows how to do it any more.
The majority of car owners do not know how good DIYS car HIFI can be. The DSP today makes results possible that are better than most of the ridiculous expensive build in “sound systems”. If the DAB+ radio stations feed the right data rate, even radio has an incredible good reproduction.
The end result of a today's a 300€ car head unit is comparable to most expensive gear a decade or two ago.
This positive on the hardware side maybe a result of the car industries furious attempts to make retrofitting impossible. In fact, with new cars, you loose the guarantee you desperately need for this driving beta test unit you just bought, if you are so brazen to fit some new speakers or amps.
The legal risk for professional car HIFI fitters is not bearable any more. So most have closed down, know how is lost and a whole form of modern art vanished.
Anyway, if you have a used car you are technically responsible for, it never has been so cheap to get incredible mobile sound. Too bad no ones knows how to do it any more.
First, thanks for all the replies. I'll get back to it but priorities at the moment have changed slightly.
I agree with Turbowatch2. I love good natural sound both in cars and at home. And while the car is a challenging environment, modern day electronics greatly improves sound in a car. As long as you put some time and effort in it and build your own install. Not those OEM optional systems. And since this is my own hobby car I only need to focus on 1 sweet spot, the drivers seat
I agree with Turbowatch2. I love good natural sound both in cars and at home. And while the car is a challenging environment, modern day electronics greatly improves sound in a car. As long as you put some time and effort in it and build your own install. Not those OEM optional systems. And since this is my own hobby car I only need to focus on 1 sweet spot, the drivers seat
Probably best not to get ahead of yourself. You still want to learn the whys and wherefores.