Passive Line Level High Pass

[noodle_snacks]

I need a temporary high pass filter or rumble filter for a subwoofer set at 40hz until i can get something active sorted out.

I had a look at: http://en.wikipedia.org/wiki/High-pass_filter Which seems to give the circuit and the equation, however i have no idea what sort of resistor value to use in order to derive the capacitance required.

Any help as to what sort of resistor value i should be looking at for a line level filter?

 

[Nigel Goodwin]

It depends entirely on what impedance feeds the filter, and what impedance it in turn feeds. Also, a crude passive filter isn't really steep enough, get a dual-opamp and build an active filter!.

 

[planet10]

More info

http://www.t-linespeakers.org/tech/filters/passiveHLxo.html

dave

 

[noodle_snacks]

I do indeed intend to build an active filter, i just want a quick and easy passive one until i have the time to do so.

How can i calculate my amplifiers input impedance and preamps output impedance?

 

[pinkmouse]

There is a thread in SS showing you how to calculate the input impedance.

 

[sreten]

Hi,

a temporary solution is to drastically reduce the
input coupling capacitor value of the sub amplifier.

As prevously stated, won't work that well.

/.sreten.

 

[noodle_snacks]

Thanks for the help, however i found a digital 250 band equaliser plugin for winamp which i will be able to use when i need the high pass filter. The filter can be set for flat response at 39hz and to be 60db down by 35hz.

http://coyote.freeweb.hu/winamp/dsp.cgi

I will probably build a steep opamp filter however since it just so happens the sound source for this little event is a computer running winamp. I have tested the plugin with a spectrogram and it does work effectively at cutting out low bass.