[Elecraft] K3S audio board for K3 upgrade?

[Jim Brown]

On Tue,3/22/2016 8:36 AM, Bill Davis via Elecraft wrote:
>   I use RX equalization AFTER I find a speaker that I can live with.

I suspect that the frequency response of the Motorola speakers are 
carefully shaped for maximum speech intelligibility in a noisy 
environment, and their response may be peaked a bit in the upper speech 
range. In the years when those loudspeakers were developed, Motorola was 
the premier 2-way radio company on the planet, and full of great engineers.

IMO, the BEST speakers and headphones for ham radio are those which have 
FLAT response (that is, equal at all frequencies) within the speech 
range (100 - 5,000 Hz) and low distortion. If they have wider response 
(like hi-fi speakers), that's still good. And if their low frequency 
response is rolled off, that's even better!

I would adjust RXEQ WHILE choosing an external speaker, tweaking 
settings for each one as you try it. If, for example, peaky response of 
a particular loudspeaker bothers you but it's a good quality (low 
distortion) loudspeaker, RXEQ can be used to reduce that peak to make 
your ear/brain happy.

73, Jim K9YC