4kHz notch filter parts values

[MaciejMaciej]

Dear Audio Enthusiasts,
I have SONIDO SFR175 fullrange speaker, 8ohm very nice unit. But in my environment I need to build a notch filter for it. Could you please help me with starting values for this filter?

The speaker in 4khz range is 7,6 ohm impedance. I need to make a 6dB deep in 4khz, lets say in slope range between 3700-4300

Thank You in advance

 

[Elvee]

Something like that: notch depth is adjustable with R3, and the notch width depends on the inductor's series resistance.
C1 needs to be mylar or PP, otherwise the depth will be affected

 

[MaciejMaciej]

Thank You very much, it looks clear to me, except one thing, the coil: is it 0,056mH ?

 

[MaciejMaciej]

Oh, I've measured impedance. And to my surprise it is 13 ohm not 7,6 as nominal.
Could you please update the values? Thank you for your help in advance

An externally hosted image should be here but it was not working when we last tested it.

 

[Elvee]

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[MaciejMaciej]

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thank you very much Elvee, I will raport effects after check