Noise Reduction

[mcp6453]

Further to my post about the failed PMD670, I have another recording of the
minister's lav mic recorded from the church sound board. However, there is
60/120Hz noise. What is a very good way to remove the noise? All I have is
Audition 1.5 and Audacity. While they do a pretty good job, I can hear the
effect of the noise reduction in the regular audio. Is there noise reduction
software that is significantly better than these two?

I've been doing audio for almost 50 years, and to have a problem like this at
such an important event after so much care and attention is horribly frustrating.

It retrospect, there were many things I should have done differently, but for
now, I'm hoping to find a solution.

[Peter Larsen]

mcp6453 wrote:

> Further to my post about the failed PMD670, I have another recording
> of the minister's lav mic recorded from the church sound board.
> However, there is 60/120Hz noise. What is a very good way to remove
> the noise? All I have is Audition 1.5

has notch filter and fft eq, best bet the fft eq, it can remove it cleanly.
Do NOT use the noise reduction for this, the sonic cost is way larger.

Kind regards

Peter Larsen

[this]@ri.t-com.hr Edi Zubovic]

-- That's right, if it's a simple hum consisting mainly of the two
frequencies, I believe there might even be a preset like "Hum Removal"
or similar for doing it and the results are good and uneventfully. You
can do it as Peter said of course, don't make too sharp a notch (Q
factor values) . But, if there's a buzz, this could be quite tricky as
the buzz is much more complex harmonics-wise and harmonics are too
numerous to fix easily...
And yes, don't use noise reduction whatever type it might be.

Edi Zubovic, Crikvenica, Croatia

[Peter Larsen]

Edi Zubovic wrote:

> -- That's right, if it's a simple hum consisting mainly of the two
> frequencies, I believe there might even be a preset like "Hum Removal"
> or similar for doing it and the results are good and uneventfully. You
> can do it as Peter said of course, don't make too sharp a notch

The actual notch used with the FFT eq was -60 and its width was from 58 to
63 Hz, the resulting notch probably half that. Extra nodes were added to
force sufficient sharpness. Another route would have been to use the
scientific filters, there is a notch section there. The FFT eq section is
good for these kinds of filterings because it alters frequency
response only, not phase response. For frequency response correction - most
of the time - the eq should be minimum phase, but not for filtering of
unrelated noise.

> (Q
> factor values) . But, if there's a buzz, this could be quite tricky as
> the buzz is much more complex harmonics-wise and harmonics are too
> numerous to fix easily...

A real wideband buzz is awful to deal with.

> And yes, don't use noise reduction whatever type it might be.

Worked well after one pass through the filter described above, the
alternative was two passes, but that still left the strangely sounding
noisefloor of the wireless mic. The treble then sounded a bit like via a 741
opamp, but it may not matter in the context. You just need to get the
settings right ....

> Edi Zubovic, Crikvenica, Croatia

Kind regards

Peter Larsen