Yes, I agree! I had brought up the same subject in the CWops Group a while back and found the same thing. When I started out in ham radio 40+ years ago, my CW sidetone was around 700-750 Hz, a very nice sweet spot. As I grew older, the sidetone frequency has been decreasing. Now at 70 years old, I am at 420 Hz and that's the new sweet spot.
I did an unscientific study by operating the Wednesday CWTs at different sidetone frequencies, just to see if there was a difference. Believe me, there was! As I increased the frequency, my effectiveness of hearing the CW signals and separating them decreased. I finally stopped at 700 Hz, as I was convinced that my hearing had changed and the lower frequency was definitely better for my ears. 73 de Jim - KE8G On Sun, Mar 14, 2021 at 7:13 PM Chris R. NW6V <chrisr...@gmail.com> wrote: > On Sat, Mar 13, 2021 at 5:45 PM Jim Brown <j...@audiosystemsgroup.com> > wrote: > > > On 3/13/2021 10:48 AM, Sverre Holm (LA3ZA) wrote: > > > A CW sidetone pitch of 400 Hz is consistent with what little research > > there > > > is on this. A paper from 1992 says that "/All subjects improved their > > > recognition as the frequency was lowered to 500 Hz, some even at 250 > Hz. > > > > As a retired designer of large sound systems, I had to learn a lot about > > acoustics and psychoacoustics (the science of how humans' ear/brain > > interprets what we hear). That science tells us that, like most of our > > senses, hearing is logarithmic both with respect to frequency and > > loudness. This means that our discrimination of one frequency as > > compared to another increases with decreasing frequency. That is, we are > > better able to separate signals from each other with RX pitch set to > > lower frequencies. > > > > 73, Jim K9YC > > Exactly right. > > I have screaming-loud tinnitus at 1700hz - which is louder than > conversation, and rises and falls in pitch and volume with every > heartbeat... Fun, fun. > > Changing sidetone from 800 to 400 made a HUGE difference in my ability to > copy through the chaos. I did so after reading an article 2 or 3 years ago > - perhaps those referenced, but I thought it was done by the USAF for > intercept operators in the late 60's - I may be mistaken. > > ut for those who might not get the implications of what Jim said: our > perceptions depend less on absolute values than on the difference between > two values. That's why when you get "hot" with a fever, you "feel cold" > (and want heat, blankets, etc.): the outside air is now "colder" with > respect to your skin temp. > > In terms of Morse, if the signal you're listening to is at 800 Hz, and the > interfering signal (or even the tone of the white noise) is at 700 Hz, the > 100hz difference amounts to just 12%. However, if the desired signal is at > 400 Hz, and the interfering signal at 300, that 100hz difference is now > 25%. At 300/200, it's 50%. Bigger differences are easier to copy. > > I did have to reprogram myself to listen at the lower frequency - > familiarity had bred contentment. > > 73 Chris NW6V > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@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 ke8g....@gmail.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@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 arch...@mail-archive.com
