Series LC Circuit in Parallel with a Speaker

Thread Starter

Sullie

Joined Mar 18, 2015
3
I opened up this speaker and saw a capacitor and a choke. So, my first thought is that it was simply a first-order Butterworth filter. But, while the capacitor is placed in series with the HF driver, as expected, it is also part of the LF circuit. For the LF driver, the capacitor and choke are connected in series, and that circuit is placed in parallel across the terminals of the LF driver.

Can anyone help me understand what the function of this circuit is and where I can find the math?

Thanks!
 

Thread Starter

Sullie

Joined Mar 18, 2015
3
Thanks,

Here's a schematic. Sorry, I don't know the value of that inductor coil.
 

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DickCappels

Joined Aug 21, 2008
5,760
As drawn, it is not the whole crossover network. A crossover would also have a low pass filter to keep the high frequencies out of the low frequency speaker (thus reducing Doppler shift of high frequencies due to the motion of the cone) is missing.
 

Thread Starter

Sullie

Joined Mar 18, 2015
3
As drawn, it is not the whole crossover network. A crossover would also have a low pass filter to keep the high frequencies out of the low frequency speaker (thus reducing Doppler shift of high frequencies due to the motion of the cone) is missing.
Thanks, Dick,

That explains my confusion. I knew it was a crossover, but I could't quite identify the function of all the parts. But that's because, as you said, some of the parts are missing.

It's out of a late-60's console. Since the LF's fire sideways (out of the sides of the console rather than out of the front), they may have thought it wouldn't be noticed, or maybe folks didn't pay much attention to physics issues like Doppler shift in 1967.

Very helpful.

Sullie
 
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