The Mudcat Café TM
Thread #133389 Message #3026471
Posted By: The Fooles Troupe
08-Nov-10 - 05:07 AM
Thread Name: Tech: Removing 60 CPS Hum
Subject: RE: Tech: Removing 60 CPS Hum
"If the mains hum is at a high amplitude, the peak of the wave may clip and extend the harmonic series right across audio frequency range."
And sadly, the frequency, although theoretically held stable, does wander about a bit... making it less effectively removed if the filters are offset by even a small amount, and the higher harmonics will thus be even further offset... also the amount of the harmonics varies over time too.
I still have a famous LP made in the 70s or thereabout of 'musique concrete' - it is just a recording of mains hum - and you would be surprised what you think you can hear in it ... :-)