how do you measure the coil in the crossover?


I am in the process of tweeking my rather inexpensive speakers, and I want to update the crossover componants. I would appreciate any help someone could give me on finding the value of the inductor coil for the low pass filter. I want to buy the alpha core equivilant.
Thanks in advance!
128x128chez
Go out and buy a DMM with inductance and capacitance capability. You can get them for less than $100 new and will get a very handy piece of equipment to have around anyway. Be sure you disconnect at least one lead of whatever you propose to measure.
you need to measure not only the inductance value but also the Q factor of the choke, which a simple DMM won't measure. An impedance bridge is required but that's simply cost prohibitive. You'll probably need to find an electronics lab to check it out.
The Q isn't going to vary that much if you stay at around the same DC resistance, which the DMM should be able to measure as well. It's certainly going to be more than close enough for any cheap speaker.

My other comment is that replacing the capacitors (use Solen/Chateauroux at the very least) is going to make an even bigger difference than the inductors.
Thanks for your responses, I should also mention that the speakers are bi-wired as well, so there are two coils or chokes per crossover. I take it that these cannot be measured for value with an ohm meter?
I don't know where you planned on buying the parts from, but you can always send the coils into Madisound, they can measure them and then sell you the "most correct" Goertz coil for your specific application.

Personally, i would tend to agree with Karls. This is, i would worry about the capacitors and internal wiring first and then take a look at the coils. If the speakers really are THAT "cheap", it might not be worth the investment that you are talking about making. Four inductors, decent capacitors, wiring, etc... will set you back over $100. If you've got an unbraced box that resonates and leaks like mad, has nothing to minimize diffraction and makes use of drivers that are low grade, putting that much money into the crossovers isn't going to help that much. In a case like that, you'd be FAR better of starting from scratch and building your own speakers. Sean
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