[Elecraft] K3: Poor sound on FM

[Jim Brown]

On 8/22/2011 3:25 PM, DL5OCD wrote:
> It would be a nice feature if the user
> could decide by himself if he want to hear down to 0Hz on FM.

Audio down to 0 Hz for speech makes no sense.  The lowest frequencies in 
the human voice are in the 100-200 Hz range (depending on the 
individual), and frequencies below about 500 Hz make almost no 
contribution to communications. There are often noise components below 
500 Hz, like power supply hum, noise in the shack (or in the car, 
including wind noise and road noise) microphone handling noise, and 
breath popping. Not only that, but directional mics EMPHASIZE low 
frequency sounds very close to the sound source (like the mouth, where 
pops are generated).

For all of these reasons, Elecraft's low frequency rolloff is a good 
thing, and there are no good reasons not to do it.  If Elecraft were to 
decide to do a setting for hams in areas that don't use low frequency 
tones, my recommendation would be to move the rolloff down to 150 or 200 
Hz.  Also, Lyle's suggestion to tweak the rolloff to a steeper slope 
could be a good idea.

73, Jim K9YC
Fellow, Audio Engineering Society