Equally revealing is the audio gram of the average over 70 American male’s high 
frequency response. I’d show you mine but it’s so bad it’s classified. 
Typically falls off dramatically in the high end over time. Mine looks like 
Niagara Falls.

Glad to have some way to electronically compensate for those years in the 
engine room and winds of the South China Sea whistling through ears on the 
bridge wing.

Ed McCann
AG6CX

Sent from my iPhone

On May 20, 2022, at 6:31 PM, Joe Subich, W4TV <li...@subich.com> wrote:


On 2022-05-20 8:36 PM, jerry wrote:
> I remember reading a magazine article many years ago...

QST, Dec 1977, Nov and Dec 1978 also the ARRL Handbook, 57th
Edition (1980).

> They showed a hole of frequencies in the normal human voice audio spectrum 
> where there is not much energy.  It was proposed to create
> a new modulation where the higher frequencies would be shifted down
> into the hole - thus letting the SSB signal take up less spectrum -
> and then shifting those audio frequencies back up at the receive
> end.

I think it was called NBVM (narrow band voice modulation).  Used
a hard lowpass filter around 600 Hz to preserve the low audio,
a bandpass filter to "select" 1500-2500 Hz, a balanced modullator
with a 3100 Hz "carrier" and pandpass filter to select the lower
sideband.  This resulted in the 1500 - 2500 Hz audio being inverted
into 600 Hz - 1600 Hz and the total transmitted voice bandwith of
just 1400 Hz (200-1600 Hz).


73,

  ... Joe, W4TV


On 2022-05-20 8:36 PM, jerry wrote:
> I remember reading a magazine article many years ago... They showed a hole of 
> frequencies in the normal human voice audio
> spectrum where there is not much energy.  It was proposed to create a new 
> modulation where the higher frequencies would be
> shifted down into the hole - thus letting the SSB signal take up less 
> spectrum - and then shifting those audio frequencies
> back up at the receive end.
>   Thinking about it...that's the sort of thing I would have expected to read 
> in Ham Radio magazine.  I miss it.
>                 - Jerry KF6VB
> On 2022-05-20 17:10, Walter Underwood wrote:
>> About seven years ago, there was an extended discussion on this list
>> about equalization settings for transmit. I collected all the settings
>> people used and posted about the majority contour.
>> 
>> https://observer.wunderwood.org/2015/09/09/transmit-audio-and-compression-with-the-elecraft-kx3/
>>  
>> 
>> wunder
>> K6WRU
>> Walter Underwood
>> CM87wj
>> http://observer.wunderwood.org/ (my blog)
>> 
>>> On May 20, 2022, at 6:07 PM, Bob McGraw <rmcg...@benlomand.net> wrote:
>>> 
>>> Oh yes it is there on many SSB signals where the OP is a male. That is 
>>> where most of the fundamental male voice energy occurs. Those signals which 
>>> look uniform across the SSB TX bandpass do sound good.
>>> 
>>> I attribute this to the fact most hams will "boost this and boost that" and 
>>> never give thoughts to attenuating.  In fact the characteristics of the EQ 
>>> in the boost mode are noticeable different than the attenuate mode.  Yes, 
>>> one can hear the difference.
>>> 
>>> In my world of pro audio, it is a practice to attenuate first and then 
>>> boost if absolutely necessary.   Hams just can't get over the fact they 
>>> must always have more.......boost boost boost.
>>> 
>>> So if ones signal is muddy or bassy, what's to do?   Attenuate the low end 
>>> first, and rarely if ever,  boost the high end.  Of course boosting the 
>>> high end will make it brighter, but not attenuating the low end will 
>>> consume lots of unnecessary transmitter power not being used for effective 
>>> communications. 50Hz - 16dB, 100Hz -16dB, 200Hz - 16dB, 400Hz - 9dB, 800Hz 
>>> - 0dB, 1.6kHz - 0dB, 2.4kHz +0dB, 2.4kHz +3dB, 3.2kHz + 6 dB.
>>> 
>>> Works for me.
>>> 
>>> 73
>>> 
>>> Bob, K4TAX
>>> 
>>> On 5/20/2022 4:30 PM, elecraft-requ...@mailman.qth.net wrote:
>>>> Message: 8
>>>> Date: Thu, 19 May 2022 02:14:10 +0000 (UTC)
>>>> From: Al Lorona<alor...@sbcglobal.net>
>>>> To: Elecraft Reflector<elecraft@mailman.qth.net>
>>>> Subject: [Elecraft] [OT] The dreaded 400 Hz hump
>>>> Message-ID:<1840135010.161126.1652926450...@mail.yahoo.com>
>>>> Content-Type: text/plain; charset=UTF-8
>>>> 
>>>> Have you studied how SSB signals look on your panadapter? I believe about 
>>>> 90% of all phone signals have a very pronounced peak at about 400 or 500 
>>>> Hz. This peak is sometimes 10 dB (or more) higher than the rest of the 
>>>> bandwidth. This is wasted power and, to my ear, makes signals sound 
>>>> muddier.
>>>> 
>>>> On the other hand, every once in a while you'll see a signal that has a 
>>>> more or less flat frequency response, without any huge peaks. Sometimes, a 
>>>> signal will actually have slightly*more*  power in the higher frequencies, 
>>>> say, 2000 Hz and higher. I've noticed that these signals have much more 
>>>> articulation and punch. But these signals are all too scarce.
>>>> 
>>>> It's pretty well known that the aging population of hams collectively 
>>>> suffers from a high frequency hearing loss. It seems to me that this is 
>>>> even more reason to carefully shape your frequency response and cut the 
>>>> dreaded 400 Hz hump.
>>>> 
>>>> R,
>>>> 
>>>> Al? W6LX/4
>>> 
>>> -- 
>>> IF ONE EXPECTS COMPUTERS AND TECHNOLOGY TO SOLVE THEIR PROBLEMS,
>>> ONE DOESN'T UNDERSTAND COMPUTERS AND TECHNOLOGY
>>> AND ONE DOESN'T UNDERSTAND THEIR PROBLEMS."
>>> 

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