[Elecraft] feedback in K3

[Jim Brown]

On 8/14/2012 8:28 PM, Joe Subich, W4TV wrote:
> Boost at the low frequencies is not only wasteful of transmit power,

Right on, Joe.  There is NO good reason to transmit ANYTHING below 200 
Hz from a ham station, simply because human speech contains no energy 
below about 125 Hz, and frequencies below about 350 Hz contribute 
nothing at all to speech intelligibility.  The only good contribution 
made by speech sounds below 500 Hz is to add some "body" to the voice.  
Since the beginnings of telephony, bandwidth has been intentionally 
limited to the range of 500-3,000 Hz, because that's what makes the 
greatest contribution to intelligibility.

In general, EVERY ham transmitter should attempt to cut off everything 
below about 250 Hz, which is the basis of my recommendation for setting 
the bottom two TXEQ bands for maximum cut, doing substantial cutting of 
the third band, and running everything else flat (0 dB).

BTW -- another VERY important reason for killing wasted power below 
about 250 Hz is that there's a lot of room noise, breathe pops, hum, and 
buzz down there.

Nearly all "ham" mics, as well as most boom mic headsets designed for 
use with computers, provide a peaky boost around 3 kHz to compensate for 
the rolloff of the filters in telephone systems and ham transmitters.  
With these mics, there is no need for any boost EQ at all.  This 
includes mics like the CM500 and the Heil mics.

Mics intended for recording, sound reinforcement, and broadcast don't 
have that peaky boost built in, so TXEQ needs to supply it. For those 
mics ONLY, a good starting point is about +8dB in the highest band and 
perhaps +3dB in the next highest band.

73, Jim K9YC