Old CRT monitors had flyback converters that often times generated loud ultrasonic audio--while it was inaudible, at the end of the day sitting in front of a monitor, my ears were reeling from the effects--loud ringing or tinnitus--really put me on edge--do not know how much hearing damage it caused, but I'm sure it did some--thankfully, with the advent of LCD monitors, those days are gone forever--or are they?
While there used to be a lot of hype about electromagnetic and gamma radiation levels from CRTs, I never heard anything about ultrasonic audio levels.
When a boy, I could hear the 15kHZ TV flyback transformer--sometimes annoying.
I suspect that there are a number of other loud sources of ultrasonic noise that are a potentially serious problem--like ultrasonic rodent repellers or burglar alarms--there used to be a few stores that I think ran them during business hours--while I could not hear them, I could 'feel' them as an oppressive something in my head...
Are there any ultrasonic noise limitation standards?
Is there equipment available to measure such? I once ran across a gas leak detector that converted ultrasonic signals to the audio spectrum.
Any thoughts out there, or similar experiences?
This might make a good project for some university student...
While there used to be a lot of hype about electromagnetic and gamma radiation levels from CRTs, I never heard anything about ultrasonic audio levels.
When a boy, I could hear the 15kHZ TV flyback transformer--sometimes annoying.
I suspect that there are a number of other loud sources of ultrasonic noise that are a potentially serious problem--like ultrasonic rodent repellers or burglar alarms--there used to be a few stores that I think ran them during business hours--while I could not hear them, I could 'feel' them as an oppressive something in my head...
Are there any ultrasonic noise limitation standards?
Is there equipment available to measure such? I once ran across a gas leak detector that converted ultrasonic signals to the audio spectrum.
Any thoughts out there, or similar experiences?
This might make a good project for some university student...