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Datasheet of speaker Answered

I recently got to take apart a set of speakers and got a nice subwoofer and tweeter out of it. The only problem, though, is that the speakers, for some reason, did not include a crossover. To calculate the values that I need for a crossover for the tweeter and subwoofer, I need the datasheet of both, or at least that is what I think. When I researched the writing on the back of the speaker, I could not find any information. How can I do this? is there another way to calculate the values of the components for a crossover? I Don't generally care what kind of crossover it is, as long as it works.

I do have a cheap LCR meter, if that makes anything easier

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0
Orngrimm
Orngrimm

11 months ago

The DC-Resistance can be measured with a simple Multimeter. This gives you the first part.
Then measure the inductance (L) with your LCR-Meter.
Now, we will dive quite deep into quite high math...
If you want a jump into the deep end, Check https://www.cpp.edu/~zaliyazici/ece307/Frequency%... for the basics in frequency response of a R-L-Filter.
At http://sim.okawa-denshi.jp/en/LRtool.php you can simulate the pure L-R-Part. It will not be very correct, as the membrane also exerts a resistance (Mechanical) against the air and therefore changes the dynamics...
https://en.wikipedia.org/wiki/Thiele/Small_paramet... Can give you another shot in the parameters as you can measure the physical parameters as well...
A good shot at the same problem as you have (Unknown speaker/driver) and finding its parameters:

0
Downunder35m
Downunder35m

11 months ago

Last time I checked the crossover was a filter and as such only the power matters but not really much what is connected....
Connect them to a low power amp and run a frequency sweep.
Select the crossover frequency in the range where both speakers are happy.

1
Jack A Lopez
Jack A Lopez

11 months ago

Uh, how many numbers do you need to build a crossover circuit for just two speakers?

I mean, there is a low-pass filter, and a high-filter, and there is a frequency where the low-pass rolls off, and the frequency where the high-pass rolls on, and it ?might ?be the case those are the same frequency.

Also I am trying to think what is the graph, or plot, that defines the frequency response of a speaker. I noticed this plot,

https://en.wikipedia.org/wiki/File:Speaker_impedan...

from this article,

https://en.wikipedia.org/wiki/Electrical_character...

Earlier today I was trying to explain power,

https://www.instructables.com/community/Dc-generat...

as the product of voltage and current, and I suggested putting a 1 ohm resistor in series with a load, and measuring the voltage across both the resistor and the load.

Impedance is the ratio of those two things, voltage and current. Impedance is more general than resistance because it is a function of frequency. You know, Z = Z(omega). Z is Z of omega, where omega is 2*pi*f, in radians per second, where f, regular frequency is just number per second, or cycles per second, or something like that.

Anyway, I guess where I am going with this is, I can maybe imagine a setup for testing the impedance of a speaker, but it would require a test signal, to give just one frequency at a time, and it would require measuring the amplitude of an AC voltage and AC current, but just the amplitudes, so phase information would be, like, not detectable using this method.

Although I wonder at how useful purely electrical measurements are. It almost seems like we should be trying different frequency electrical signals, and measuring how much sound power is emitted from the speaker, like, by listening to it with human ears, or with machine ones.

Another idea for your crossover is to just take a wild guess at where the crossover frequency should be, e.g. 1 kHz or 500 Hz. Then build that circuit. Then plug the speakers in, in the expected way, and listen to what it sounds like.

Then swap the speakers, feeding low frequencies to the tweeter, and high frequencies to the voofer, and see if that sounds (see if sounds? hear if looks?) noticeably worse.