Hearing ultrasonics?

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This reminds me of the time I found a bat in my car. I looked in the back seat, saw half a banana there and wondered where it came from. leaned in close, was about to touch it and it turned out to be a dead bat with black and yellow shading :joker:
It musta cooked in the heat or something.. saw the black interior and though it was a cave

I have no idea of the relevance of this story:bored:
 
Eva said:
I would just like to point out that there is nothing special in hearing 15Khz or 16Khz horizontal oscillator signals from TV sets. Also, most people can perceive 20Khz provided enough SPL, that's the parameter that matters, perception threshold.

Nobody said any different.

BTW, I can hear several different bat vocalizations as well, and I don't claim I have ultrasonic hearing. In fact, Flyback transformers don't bother me much anymore. It used to be that when I walked into the stores where they have a wall of televisions it was so annoying I would have to move on. Now I can only hear them after my ears equalize from yawning or such.

My old TV had a bad flyback whine and I could measure 70dB with my dB meter and it was ~10dB down at 16k - so 80db is below my threshold at that frequency....except for right after my ears pop - then it is about 70dB.

Once you get above ~25k, that is la-la land and anything heard is most likely a nonlinear function of the ear - where ultrasound is causing audio artifacts - especially at high level. I ran some loud ~100-110dB 20Khz through some headphones once and got a really fuzzy 500-1k tone (sounded like 3 or four closely spaced tones playing simultaneously) that couldn't be measured in the phone output, so my ear apparently distorted and "manufactured" audible tones from the high SPL sine waves.
 
Even if you don't consciously hear it, I'd still bet it's registering in some part of your brain.

If I take a 7 mhz test tone and crank up a bit of wattage on my power amp, it doesn't take long before I start feeling a bit goofy and thick headed. That's because the brains peak resonance frequency is between 6-8 Hz, oddly enough the same as jello. If I hook up my ultrasonic/subsonic tranducer and get with in a couple feet of it, the effect is intense and you feel like your brain is linked to the transducer. The saw tooth being the most agressive.
I'm suspecting the correlation here is, you can train yourself to sense and possibly hear these lower and high sound spectrums that for most humans, don't consciously register. Some of the higher pitches that hurt my ears aren't always audible and the sensation is not one of noise but just that, a sensation in my inner ears.
 
Not anymore, but I used to hear bats, and occasionally those crummy motion detecting piezoelectric burglar alarms. They were erratic if turned on and off I was told, so they were left on. And of course some television sets were a real bother.

A friend's wife, in her 50's, used to hear the bats until quite recently, and may still. ( I haven't asked lately.)

PS It changes with ear elasticity and bone size. That's why kids cringe at the chalk/blackboard squeals that don't bother the teacher at all.
 
... 7 mhz test tone and crank up a bit of wattage on my power amp,....

Wonderful. Show me an audio amp which has still some gain at 7MHz.
Didn't any bat bite you when you were a child?
Or maybe you cannot see your reflection in the mirror?

If you want to examine how high you hear use function generator, set 1Khz volume to nearly pain and tell second person to switch on and off some freqs. You tell if you hear or not.
 
I have issues with TV's and monitors sometimes..My old monitor got "the boot" because it wouldn't shut up! It drove me nuts! :mad:
I hate that squealing noise..

A friend and I once did an experiment..we used a 555 timer and a Horiz.Output transistor from an old TV,and a Motorola piezo horn tweet...all powered by a 9V battery..
We set it to oscillate *just* above the point where we could hear it,and set it under the couch and waited for his roommate to get home.. When he walked in he seemd like he was in a decent mood..but 5-10 minutes later he seemed really aggrivated,and didn't seem to know why..untill we showed him the 'gadget'..
It's interesting how high-freq noises you might not even 'percieve' can alter your mood.


I actually got into a bicycle 'accident' one night while riding through a park..I was too busy looking up at the bats I heard to notice that I was about to run into a steel tether-ball pole.. (yea,I broke the weld on the bottom of the pole,and it fell over on my wrist and smashed it to pieces -very painful.)
My bicycle however,was pretty much perfectly fine,just a minor scratch.

Dang bats.. :dead:
 
In the early days of CDs, I found them unlistenable due to a HF 'whistle' clearly audible during louder passages. I never did discover its exact origin, but it was perfectly clear on a wide range of players. Either CD has improved or my ears have deteriorated since then, as I no longer hear it!
 
Here's something odd. Was out in the car this evening and saw something in the road that looked like an animal but too small and it matched the pavement of the road. As I came up on it another car was coming around the bend so there was no bothering to swerve around it. This fury creature hops up and starts to fly and does so right into the fender of my car.
I hit a bat:eek:
Obviously I share this story for the irony
 
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