[Elecraft] [K3] Hearing aids, meet K3

[Ron D'Eau Claire]

Sort of a "benchmark" for essential audio bandwidth is to consider the
current practice in the A.M. broadcast industry, at least in the USA. 
A recent report in "Radio World" notes that most analog A.M. broadcast
receivers today have a bandwidth of less than 5 kHz. 

Listener tests showed that most people were not aware of a difference when
the bandwidth of speech or music, including classical music, was reduced
from 10kHz to as little as 7 kHz. Of course there is not a lot of classical
music broadcast on A.M. these days.  

So if you enjoy music on your A.M. radio, note that it's unlikely your radio
is reproducing much of anything above 5 kHz. That's especially true of car
radios that suppress the higher frequencies to reduce background noise on
weaker A.M. stations. 

73, Ron AC7AC