[Elecraft] ESSB

[Joe Subich, W4TV]

 > Another way to look at this is that our ear is most sensitive to
 > frequencies around 2 kHz (roughly) and so you really want to put as
 > much of your power in that region as you can. In this way, you're
 > using the response of the other op's ear to your advantage.

Not entirely ... equal loudness curves show peak sensitivity around
3 KHz independent of sound pressure levels.

Human voice has very little energy between 700 Hz and 1200 Hz with most
of the power (fundamental energy from the vocal chords) between 200 and
500 Hz with sibilance and unvoiced energy (sounds made with the tongue,
teeth and lips) that contribute to "definition" (consonants) in the
1400-4000+ Hz range.  The ear needs a balance (although not 1:1
relationship) between lows and highs for best intelligibility.

While I do not try for maximum "punch" like K9YC, what he suggests is a
good starting point.  I don't completely roll off 200 Hz but set it to
about -6dB.  I also set 800 Hz to -6 or -10 dB which helps eliminate
background noise. Then I use a 3 dB/octave rise at the high end: +3 at
1600, +5 at 3400 and +6 at 3200.  With the K3 compression engaged, the
rise means the highs will be "more dense" (or clipped harder).  They
will not be any louder than the lows but they will be more pronounced
through the noise and *will* contribute to enhanced intelligibility
without sounding "rough," "muddy", "tinny" or "narrow".

Excessive low frequency response generally causes voices to be muddy.
Excessive high frequency energy with too little low frequency response
causes voices to sound "tinny" and too much mid-range (excessive low
and high cut) causes voices to sound hollow.

73,

   ... Joe, W4TV


On 2014-11-17 2:05 PM, Al Lorona wrote:
> I'm glad K9YC answered your question. If you heard Jim's signal
> during the SS this weekend then you got to hear what the shaping he
> is describing sounded like. His audio was very piercing but clean.
> It's not what I would want to hear during a long ragchew with him,
> but his purpose was to project his intelligibility across 40 meters
> for the purpose of a 30-second contact.
>
> Another way to look at this is that our ear is most sensitive to
> frequencies around 2 kHz (roughly) and so you really want to put as
> much of your power in that region as you can. In this way, you're
> using the response of the other op's ear to your advantage.
>
> To further paraphrase what Jim said, when it comes to compression, "A
> little is good, but more is not better," as evidenced by so many
> shockingly bad signals this weekend. I wish someone would undertake a
> project to send contesters recordings of themselves. I happened to be
> listening when a station with especially egregious audio called K9YC,
> who gave the op a quick but honest report at the end of his exchange.
> Who knows if that station will heed the advice for the next contest.
>
> Al  W6LX
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