[Elecraft] Psychoacoustics (Was: K3 and Preamp)

[Alan]

On 09/06/2014 04:26 PM, Jim Brown wrote:
> ...
> From Psychoacoustics (the science of how the human ear-brain 
> combination works), we know that we process sound in narrow chunks of 
> bandwidth called "critical bands." The ear tends to process sounds 
> within that band together, so when the filter gets too narrow, the 
> filter skirts fall with the critical band and ringing begins to 
> obscure the desired signal. The width a critical band varies with the 
> sound spectrum, and is in the range a 1/3 octave to 1/6 octave. An 
> octave is a 2:1 ratio of frequency.

That corresponds with my intuition.  I long ago figured out that when 
using a very narrow-bandwidth filter, I can copy a lot better if I lower 
the filter center frequency.  For example, with a 50 Hz bandwidth I can 
copy better if I tune the filter from the standard 800 Hz down to 300 Hz 
or so.  That's about 1/5 octave.

Alan N1AL