[Elecraft] K3S Noise reduction Test

[Jim Brown]

EXACTLY RIGHT!  The scientific study of how we hear and perceive sound 
is called psychoacoustics, and is one of many important disciplines of 
the Acoustical Society of America. Early work at Bell Labs and at 
universities like MIT and Harvard became the basis for stereo.

Some of the first published work was by Joseph Henry, whose name is on 
the unit of inductance in recognition of his invention of meters and 
motors. It was Henry who first observed (around 1850) that when the same 
sound is heard from two directions, the one that arrives first at our 
ears tells us where the sound is coming from. This fact is the basis of 
the Bell Labs stereo patent, and makes it far superior to the Blumlein 
work published a year or so earlier.

73, Jim K9YC

On Wed,6/21/2017 1:14 AM, David Woolley wrote:
> Noise reduction is about reducing subjective noise for the listener, 
> not about reducing some engineering measurement.  An instrument is 
> likely to generate some very simple, or even pure tone, signal. With 
> the sorts of strategy used for noise reduction, and very aggressive 
> settings, you could obtain almost perfect results on such a signal, 
> but those same settings would make human speech completely 
> unintelligible.
>
> The big challenge for noise reducers is deciding what is human speech 
> and what is noise. That's much more difficult than identifying a pure 
> tone.