High Pass Line-Level Crossover

cmcdonnell · 3561

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Offline cmcdonnell

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on: July 03, 2010, 05:39:20 PM
I use a powered subwoofer with my full range Fostex FE168E speakers.  According to their data the impedance begins to rise below 200 hz and peaks at 50 hz at almost 70 ohms.  Is there a simple line-level crossover that will roll off the frequency below 200 hz with minimal sound degradation and hopefully allow my Paramours to push a little harder?

Chuck



Offline Paul Birkeland

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Reply #1 on: July 04, 2010, 08:38:12 AM
You can decrease the value of the .1uf coupling cap in the paramour.  Pick the -3db frequency you would like, then C=1/(2*Pi*R*F) where R is the grid resistor in ohms (usually 249,000), F is the frequency you picked, and C is the coupling cap value in Farads. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline cmcdonnell

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Reply #2 on: July 04, 2010, 11:20:02 AM
Pi is 3.14?




Offline InfernoSTi

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Reply #3 on: July 04, 2010, 12:39:59 PM
Pi is 3.14?

Yes, you are correct: 3.141593

John Kessel
Hawthorne Audio AMT K2 Reference Speakers
Paramount 300B w/MQ All Nickel Iron,  Mundorf S/G 5.5 uF,  and  Vcap Teflon .1 uF
Auralic Taurus Preamp/Auralic Vega DAC/Auralic Aries Streamer
and lots of room treatments!


Offline Grainger49

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Reply #4 on: July 04, 2010, 12:54:25 PM
Not that you can buy a capacitor to three, much less seven, places.  But you will get a very accurate calculation.



Offline cmcdonnell

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Reply #5 on: July 04, 2010, 05:26:53 PM
Thanks for the info.  I ordered 3 different values and I will try to do some testing when they come in.  According the the calculation it comes to about .003 mf.