[Elecraft] The Dreaded 400 Hz hump

[Walter Underwood]

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 <rmcgraw at 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-request at mailman.qth.net wrote:
>> Message: 8
>> Date: Thu, 19 May 2022 02:14:10 +0000 (UTC)
>> From: Al Lorona<alorona at sbcglobal.net>
>> To: Elecraft Reflector<elecraft at mailman.qth.net>
>> Subject: [Elecraft] [OT] The dreaded 400 Hz hump
>> Message-ID:<1840135010.161126.1652926450733 at 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."
> 
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wunder at wunderwood.org