Peter Chuang
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- Joined
- Feb 22, 2022
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When I look at speaker impedance graph, interestingly, I found a lot of speakers having impedance peak around crossover frequency.
Take focal 906 measurements by @amirm for example.
There is a peak around 2.5khz.
I understand that tweeter have a high pass filter, while the woofer have a low pass filter.
Impedance of each filter having impedance function as R+jX.
In a certain frequency, where HPF and LPF connect parallel can achieve imaginary part of the impedance to be canceled leaving R only.
(one of the jX of HPF/LPF is positive while the other is negative which makes R+jX(LPF) // R+jX(HPF) = R_eq +j0)
The question is, why R is so high even higher than impedance of the driver unit?
If the woofer driver itself is 4~8 ohm, and tweeter also 4-8 ohm, how come it result in 30+ ohm at 2.5khz.
Can this be explained in the topology?
Thanks in advance.
Take focal 906 measurements by @amirm for example.
There is a peak around 2.5khz.
I understand that tweeter have a high pass filter, while the woofer have a low pass filter.
Impedance of each filter having impedance function as R+jX.
In a certain frequency, where HPF and LPF connect parallel can achieve imaginary part of the impedance to be canceled leaving R only.
(one of the jX of HPF/LPF is positive while the other is negative which makes R+jX(LPF) // R+jX(HPF) = R_eq +j0)
The question is, why R is so high even higher than impedance of the driver unit?
If the woofer driver itself is 4~8 ohm, and tweeter also 4-8 ohm, how come it result in 30+ ohm at 2.5khz.
Can this be explained in the topology?
Thanks in advance.