[sdiy] tinnitus (WAS Lossless synthesizer demos)

[Richie Burnett]

I think I've heard about the Tensor Tympani Muscle being implicated as a 
possible cause for this.  It's a muscle that normally contracts to reduce 
the sensitivity of the ear in the presence of loud sounds, (a sort of AGC,) 
but the process can malfunction leading to a range of symptoms classed as 
"Tensor Tympani Syndrome".

https://en.wikipedia.org/wiki/Tensor_tympani_muscle

It mentions that muscle contraction produces noise... "Fast twitch fibers 
produce 30 to 70 contractions per second (equivalent to 30 to 70 Hz sound 
frequency)".  Some people hear rumbling if they close their eyes really 
tight, etc.

The Tinnitus discussion is interesting.  I turned 46 last year and just 
started to notice degradation in my hearing and Tinnitus around 10kHz 
particular at night.  I could easily have tried to blame this on the excess 
noise produced during the day by my young daughter, or a symptom of too much 
caffeine intake in a futile attempt to be able to keep up with her! ;-) 
...but sadly it probably has more to do with listening to music loud in my 
younger years.  I've also listened to high-frequency sweeps at elevated 
volume from time to time searching for aliasing artefacts.  Something which 
was foolish in hindsight and definitely more scientifically and safely 
quantifiable in a spectrogram anyway!  Lesson learnt: Be kind to your ears.

-Richie,




-----Original Message----- 
From: Bernard Arthur Hutchins, Jr via Synth-diy
Sent: Saturday, April 24, 2021 9:35 PM
To: synth-diy at synth-diy.org
Subject: [sdiy] tinnitus (WAS Lossless synthesizer demos)





LF Tinnitus ???

Since the subject of “ordinary tinnitus” (HF; say 5 kHz – 10 kHz) has 
appeared here as a topic, please humor me in allowing mention of the 
“World-Wide Hum” (WWH, sometimes Taos Hum, etc.) which is a mysterious LF 
hum (like an idling diesel engine in the distance - perhaps 30 Hz to 100Hz – 
I hear 64 Hz), often 24/7/365, the exact nature and cause of which is 
largely unknown.

Few people hear this (perhaps 2%), but observations are confounded by real 
trucks, refrigerator units, failing power transformers, etc., as well as 
(conspiracy directed) entertaining suggestions of government mind-control or 
underground invasion tunnel drilling, cell towers, etc.   Few good audio 
engineers are hearers and participating investigators.

This Hum is likely an individually generated (internal) artifact – not a 
real physical sound; a LF tinnitus.  Importantly and diagnostically, various 
“impulsive” INDIVIDUAL ACTIONS (vigorous head-shake, exhale, grunt) seem to 
interrupt the WWH for about ½ a second, after which it is found to have 
ramped back up.  This ramp-back-up timing reminds an audio engineer of AGC, 
which in turn might suggest actions of protective muscles in the middle ear 
(supposition here).



For those interested, Dr. Glen MacPherson maintains an excellent website on 
the WWH:

https://hummap.wordpress.com/

and I have posted on my EN site Webnotes linked here:

http://electronotes.netfirms.com/ENWN56.pdf



-Bernie







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