Resonant Circuit 1

[rsbuck]

Been 35+ yrs since taught and haven't used since. Outside my office is a plant loudspeaker. It has two wires powering it. The PA system was changed to where there is a very loud and annoying 1000HZ tone just before the message. I would like to filter out the 1000HZ with a choke coil and a variable capacator. Could someone plug in the values and whether it would be series or parallel. If this idea won't work is there anything I could do to disable this tone locally and not at the main amp?

 

[itsmoked]

Let me point out that human speech all occurs around 1000Hz..

You will have other problems if you try to filter out this passband.

You would do much better finding where the hum is coming from and fixing IT instead.

 

[OperaHouse]

That is probably an annunciating tone. If I were to attach a Rube Goldberg solution to this, I would attach a normally open relay to the speaker line. A small circuit monitoring the speaker line would have an on delay before closing the relay since these tones have a consistant time period. And of course the relay would have an off delay for those pauses in speach.

 

[rsbuck]

Excellent idea!