Selective CNF?

[Dan McDonald]

Is it possible to put the CNF in a multifilter so that it only operates on certain frequencies, like above 6khz for example?

I'm thinking specifically of the auto spectrum CNF. What I'd like to do is be able to have it operate on the high end to eliminate hiss without introducing artifacts in the middle range.

For example, with a really hissy tape where there's very little signal above a certain range (but still some), I'd like to gently introduce the CNF over an octave or so, so that it gets very aggressive where there's nothing but noise, but not very aggressive where there is signal, and not working at all where there is a lot of signal in the lower ranges.

Sort of like a low-pass filter, but using the CNF instead of a low-pass filter.

Dan

[Craig Maier]

Yes and No. Yes, you can do that with the CNF filter operating in Normal or Spectral Subtraction Modes. No, it can not be done in Auto CNF mode because the system is always re-calculating it own noise fingerprint adaptively (unless you hit the "freeze" button).

So, if you are willing to operate in Normal or Spectral Subtraction Modes, simply drag all of the blue inflection points (blue dots) on the graph below 6 KHz all the way to the bottom. Do this after you take a fingerprint or use a standard preset fingerprint already in the system. Then, those bands below 6 KHz will not be in effect any more.

[Dan McDonald]

Thanks Craig -

That was what I thought, but I was thinking that there might be a 'trick' to accomplishing that with the Auto CNF.

Dan