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Rasta Robert

On 2016-05-29, wrote:
This resistor is very simple. It will have
stereo RCA in and out, and 1/8" mini
in and out.

All it will do is attenuate 2.5khz by 3
dB, with a Q wide enough to modestly
affect frequencies from 1kHz up to 4kHz.

Essentially to mildly scoop out those
audio frequencies humans most readily
hear. One could plug a line source or
phone into it, and RCA out, IE, to a
stereo amp. One could use the built-
in tone controls('Bass', 'Treble'), to
tailor the ends of the bandwidth to
taste.

Result? A smoother, less intrusive
sound at background or concert-
hall levels.

What materials do I need?

So not a resistor, but a filter,
a notch or band stop filter to be
precise.
You will at least need resistors and capacitors,
possibly one or two coils.

https://en.wikipedia.org/wiki/Band-stop_filter
http://www.radio-electronics.com/info/circuits/rc_notch_filter/twin_t_notch_filter.php
http://www.hobby-circuits.com/circuits/audio/audio-filter/590/rc-notch-filter-twin-t
http://www.instructables.com/id/Passive-Filter-Circuits/

Making it a passive circuit will also
attenuate the signal level, so you
might need some active amplification
in it to recover that.

http://www.circuitsstream.com/2013/06/simple-notch-filter-uses-operational.html
http://www.radio-electronics.com/info/circuits/opamp_notch_filter/opamp_notch_filter.php