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50/60 Hz Hum/Buzz Notch Filters

Sometimes, an unwanted and nasty 50 or 60 Hz (Hertz) buzz or hum is present in audio, and obviously needs to be removed.

Screenshot: 50/60 Hz Hum/Buzz Notch Filters

In the majority of cases, this buzz is induced by the AC mains that runs into your home, which is normally 50 or 60 Hz in frequency (depending on where you are in the world). Sometimes it's caused by proximity to the AC mains, and sometimes it's caused by a power supply that does not have sufficient DC smoothing. Regardless of cause, it needs to be removed.

These circuit are "notch filters" that are specifically tuned to the 50/60 Hz hum, so that it can be (relatively) safely removed, thereby providing a more pleasurable listening experience.

Please note that these circuits must be used as "early" as possible in the path of audio (but of course not before the hum is actually introduced). That is to say... you won't be very successful in removing the hum after it has gone through an amplifier or processor. You should filter the hum BEFORE it goes through any amplification or processing. If on the other hand a processor or amplifier actually introduces the hum, then you should try to find a fix for that.

 
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COMMENTS
SunFM107 says: (December 29 2007, 8:01pm)

I wonder if someone can help me...

I have a vicious hum/buzz in my audio mixer, that seems to be a result of a nearby fm radio transmitter. The transmitter operates on 106.7 fm with an output of 250 watts. Every time the transmitter is turned on the hum comes and every time it's turned off it goes away.

Does anybody know if this filter will be able to help?

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