60 cycle hum & notch filter

[Guest]

I am just getting started using DCart, version 2.02 (yes, I know, it's just been sitting there for a couple of years waiting for me to assemble other stuff).

I just tried to remove some 60 cycle hum using the notch filter and find any settings which made a noticable difference. The recording had passed from 78 records (in the 1950's) to reel-to-reel tape to cassette before I got it, and the hum is in the lead-in and lead-out sections from the records. I tried varying the center frequency (not much, but a bit) and widths from .1 to 2.0, none of which seemed to do anything. If I blow up a section I can SEE the waves -- I counted ten of them and used the markers to check the interval and it was indeed about 58 cycles -- suppose tapes may have streatched, or my measurement could be off.

So, what should I try next?

Cyril N. Alberga

[Craig Maier]

Re: 60 cycle hum & notch filter

If the notch filter is not doing the job, then the signal is not hum but buzz. Buzz is hum with lots of harmonic content. Hum is a pure sinusoidal tone. If you have Buzz rather than hum, then you will need to use the Harmonic Reject Filter found in the DC Art 32, Diamondcut Millennium, or the Diamondcut Live programs. Demo's of these programs can be downloaded from our website located at www.diamondcut.com.