[Elecraft] W2IHY 8 band equalizer and EQ Plus

[Jim Brown]

On Tue, 27 Apr 2010 22:49:14 -0400, Lu Romero wrote:

>While I agree in principle, in practice, there are some high
>frequency sibilance "formants" that need bandwidth up to and
>including 2.8kHz to almost 3kHz to be well understood. 
>There are also some harmonics, especially in male voices,
>that go down below 300-400 Hz. 

YES. Because I've made my living designing sound systems for 
highly reverberant churches, this is something that I've had to 
carefully study. It is VERY well known that the most important 
octave bands for speech intelligibilty are the octave bands 
centered on 1,000 Hz and 2,000 Hz. Those bands range means from 
about 720 Hz to about 2.8 kHz. The 500 Hz is next most important 
(extending down to about 350 Hz), followed by the 4000 Hz octave 
band. Human knowledge about this is VERY well established, and 
dates back to the earliest days of telephony. That's why it's so 
important to boost the mic response to compensate for the rolloff 
by crystal filters between 2 and 3kHz!   

73,

Jim Brown K9YC