I may have cracked mic and system noise.
First I did some measurements with a MKH416 deep under bedclothes. I
filtered out the house noises with a steep HPF below 5kHz leaving a
mic and mixer hiss which was 54dB below my "outdoors" speaking voice
at 1 metre.
I then sampled this hiss in Audacity 3.1 and used this as a noise
sample using their noise subtraction command. With various recordings
at the same level setting, Audacity took out the sample mic noise on
all the recordings including a recording of hiss up to 20kHz.
Comparing before and after in real time and also slowed down 10 times,
I could hear no difference between the noise reduced version and the
original except the absence of mic hiss. There were no audible
artifacts or "gravel" effects.
Next test will be with cheap =A39 mics to see if I could have saved two
zeroes on mic costs. :-)
David
David Brinicombe
North Devon, UK
Cogitocogito ergo cogito sum - Ambrose Bierce
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