Need a notch filter calculator.

GuyPanico · 17th July 2006, 02:35 AM

Are there any notch filter calculators? I'd like to tame the mountain at 7khz I have. The calculator I did find will only attenuate the peak -3db. I need more like -6db however.

jamikl · 17th July 2006, 02:44 AM

There is an Excel one available called notchcalc. Can't remember where I got it from. Displays the depth and the width of what you calculate on the sheet. This may help. Googling under that name mya find it.
jamikl

jamikl · 17th July 2006, 02:46 AM

users.d-web.com/dbrown/speakers/speakers_files/notchcalc.xls
jamikl

jackinnj · 17th July 2006, 03:24 AM

a notch filter is a "band reject filter" -- sort of like a the hole in a donut -- you sum a high pass and low pass filter -- use resistors to lower the Q -- it can be done with passive devices if you have a lot of patience.

best to get a CAD program like SwitcherCad (free from linear tech) and play around with the RLC values.

you can also make some valiant assumptions with respect to the input impedance of the amplifier and use an RC notch filter, or just fix the input value of the amplifier with a resistor and plug and play.

an active notch filter can have the Q continuously adjusted. most often people use active notch filters in applications like hum removal or to notch out the fundamental frequency for analysis of distortion residuals.

Cal Weldon · 17th July 2006, 02:47 PM

I like to use this one

http://www.mhsoft.nl/spk_calc.asp

17th July 2006, 02:35 AM	#1
GuyPanico diyAudio Member Join Date: Mar 2005 Location: Euless, TX	Need a notch filter calculator. Are there any notch filter calculators? I'd like to tame the mountain at 7khz I have. The calculator I did find will only attenuate the peak -3db. I need more like -6db however.

17th July 2006, 02:47 PM	#5
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	I like to use this one http://www.mhsoft.nl/spk_calc.asp __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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17th July 2006, 02:44 AM	#2
jamikl diyAudio Member Join Date: May 2005 Location: Melbourne	There is an Excel one available called notchcalc. Can't remember where I got it from. Displays the depth and the width of what you calculate on the sheet. This may help. Googling under that name mya find it. jamikl

17th July 2006, 02:46 AM	#3
jamikl diyAudio Member Join Date: May 2005 Location: Melbourne	users.d-web.com/dbrown/speakers/speakers_files/notchcalc.xls jamikl

17th July 2006, 03:24 AM	#4
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	a notch filter is a "band reject filter" -- sort of like a the hole in a donut -- you sum a high pass and low pass filter -- use resistors to lower the Q -- it can be done with passive devices if you have a lot of patience. best to get a CAD program like SwitcherCad (free from linear tech) and play around with the RLC values. you can also make some valiant assumptions with respect to the input impedance of the amplifier and use an RC notch filter, or just fix the input value of the amplifier with a resistor and plug and play. an active notch filter can have the Q continuously adjusted. most often people use active notch filters in applications like hum removal or to notch out the fundamental frequency for analysis of distortion residuals.

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