Looking for an audio filter circuit

[Dr Chris Andrews]

Does anyone have a circuit for a low pass audio filter with variable cut-off
frequency? An added nice feature would be a way of varying the damping ratio
of the filter - i.e. being able to select any extra boost at the cut-off.

Similarly an audio high pass filter with variable cut-off and or damping.

Thanks

Chris
ca.also@pobox.com

 

[Phil Allison]

"Dr Chris Andrews"

Does anyone have a circuit for a low pass audio filter with variable
cut-off frequency?

** A pot and a cap in series will do that.

An added nice feature would be a way of varying the damping ratio of the
filter - i.e. being able to select any extra boost at the cut-off.

** " any " ????

Care to define your terms and goal ???

Similarly an audio high pass filter with variable cut-off and or damping.

** We talking active ?

Passive ??

Variable slope ??

Speaker x-over ??





.................. Phil

 

[Dingo]

Look here:
"Filter Design in Thirty Seconds"

http://focus.ti.com/lit/an/sloa093/sloa093.pdf

Hope that helps


"Dr Chris Andrews" <chrisa@pobox.com> wrote in message
news:dQ_Hd.126644$K7.100937@news-server.bigpond.net.au...

Does anyone have a circuit for a low pass audio filter with variable
cut-off
frequency? An added nice feature would be a way of varying the damping
ratio
of the filter - i.e. being able to select any extra boost at the cut-off.

Similarly an audio high pass filter with variable cut-off and or damping.

Thanks

Chris
ca.also@pobox.com

 

[Dr Chris Andrews]

Many thanks to everyone who replied. There are some great ideas there that
I'll take on board.

Chris



"Dr Chris Andrews" <chrisa@pobox.com> wrote in message
news:dQ_Hd.126644$K7.100937@news-server.bigpond.net.au...

Does anyone have a circuit for a low pass audio filter with variable
cut-off frequency? An added nice feature would be a way of varying the
damping ratio of the filter - i.e. being able to select any extra boost at
the cut-off.

Similarly an audio high pass filter with variable cut-off and or damping.

Thanks

Chris
ca.also@pobox.com