Sannikka, Martin. To ACNC in Support of Waubra Foundation
Waubra Foundation’s valuable independent research into inaudible hearing sensations must be encouraged and financially supported. Please do not shoot the messenger.
Dear M/s Pascoe,
Our grandfathers decided that if the tip of the needle of an analogue sound level instrument moves 125 mm per second it is called ‘Fast Response’. ‘Slow Response’ was 8 times slower at only 15 mm/s. Instruction manuals preferred slow response. It was discovered later that human ear response time is more than 1000 times faster than the ‘Fast Response’.
It was difficult to use tape recorders correctly, as their practical dynamic range was 50 dB.
If low frequencies were present, you had to make the recordings using A-weighted settings . Subsequently, you could not listen the recordings, as your own ears A-weighted the recordings the second time and the low frequency information was lost.
Microphones were calibrated using 250 Hz ‘piston phones’, which successfully passed moisture droplets or dust on top of the diaphragms. Higher frequencies overloaded the diaphragms making the readings incorrect even the official calibrator passed them.
Operators of ultrasonic cleaning baths ignored all the hearing protection instructions, as there was no audible noise. They blamed the fumes from the bubbling cleaning liquids for their headaches, tinnitus, balance lose and sleeping problems.
Modern technology has solved all the above and other technical problems.
The big problem now is convincing the politicians that infra and/or ultra sound noise sensations can cause psychological and psychiatric health problems, which cannot be solved using traditional A-weighting methods.
WAUBRA FOUNDATION’s valuable independent research into inaudible hearing sensations must be encouraged and financially supported. Please do not shoot the messenger.
(Retired NATA (National Association of Testing Authorities) Signatory in Community Noise Assessments)