[Elecraft] Is there a reason the receive is so Skinny

[Jim Brown]

On 4/27/2014 2:41 PM, Larry Wassmann wrote:
> Do you think any of us audio guys had any influence?

W4TV is "an audio guy" -- specifically a retired broadcast engineer who 
worked in TV. So am I "an audio guy" -- specifically a retired audio 
professional who worked in sound reinforcement, recording for broadcast 
and CD releases, and before that in broadcast radio and TV. I'm also a 
Fellow of the Audio Engineering Society.

W4TV is entirely correct in his recommendations, and the only extent to 
which we differ is that I strongly recommend an octave less low 
frequency bandwidth than he does. Using the TXEQ built into the K3, I 
recommend full cut of the three lowest octave bands (50, 100, and 200 Hz 
centers), and 6dB cut of the 400 Hz band.

Why? Because as a consultant specializing in the design of very high 
quality sound systems for acoustically challenging performance and 
worship spaces, I learned that 90% of all speech intelligibility is 
conveyed between 400 Hz and 5 kHz, but that voices and room noise have 
lots of energy below 400 Hz that wastes TX power. The octaves below 500 
Hz contain about half of the ENERGY in speech, but contribute only about 
5% to speech intelligibility. So getting rid of that wasted power and 
cranking up the mic gain by 3dB is the equivalent of doubling our output 
power!

The octave above 3 kHz adds only 10% to speech intelligibility, but 
burns twice as much RF bandwidth. That's OK on a dead band, but it IS 
selfish and inconsiderate when others want to use that spectrum. As 
Riley Hollingsworth (the enforcement guy at the FCC who cleaned up the 
ham bands before retiring several years ago) has said both in print and 
at a speech at Dayton, "if you want to transmit wideband audio, get 
yourself a broadcast station." Riley is active on the ham bands. I've 
worked him several times during contests.

Why do rigs include equalizers? First, because hams want them, whether 
for a good reason or a bad one. HOW we use them is what matters.

73, Jim K9YC