[Elecraft] K3 RX AUDIO

[Al Lorona]

That could be what it is. The "hissy" sound that some folks are hearing is probably simply a passband that's unusually flat. Those interested should familiarize themselves with the plots on Barry N1EU's page: http://n1eu.com/K3/K3_notes.htm .
 
So, I am not sure why, if at say, 2.8 kHz you find the "hiss" objectionable, you wouldn't simply limit the upper cutoff frequency to 2.75 kHz??? I find 3.4 kHz too noisy; I leave my HI CUT frequency far below that point, always. That's why that control is variable.
 
There might be another factor involved. I don't recall if I made this point before-- and I apologize if I am repeating myself-- but I find that hams who grew up copying signals buried in QRM on less-than-perfect receivers tend to do much better later in life dealing with the psychoacoustical effects this thread has morphed into discussing. But this is only an anecdotal observation and I think some psychology student somewhere should do their dissertation on this!
 

> The K3 does have a very flat passband with steep skirts out to the
> hi-cut value. I am guessing that the flat passband is what is
> bothering you.


 
For a similar reason, we have hams who dislike copying stations who are less than S9. 
 
The 'ear-brain filter' that you hear about is an amazing thing, but especially if the skill to use it has been cultivated from a young age.
 
Al  W6LX