343/2001 CONTRACT RESEARCH REPORT Damage to human hearing by airborne sound
... For ultrasonic components above 20 kHz, the limits were set to avoid hearing damage in the audible (lower) frequencies. One-third-octave band levels of 105-115 dB were observed to produce no temporary hearing loss, and were therefore judged non-hazardous in respect of permanent hearing damage. Since ...
... For ultrasonic components above 20 kHz, the limits were set to avoid hearing damage in the audible (lower) frequencies. One-third-octave band levels of 105-115 dB were observed to produce no temporary hearing loss, and were therefore judged non-hazardous in respect of permanent hearing damage. Since ...
Are some people suffering as a result of increasing mass exposure
... main tone at approx. 19.2 kHz) and (b) a calibrated microphone in a railway station. In (a) the temporary placement of the author’s finger over the microphone (as indicated by the vertical arrows) allows the signal to be confirmed as acoustic and not electromagnetic pickup (see appendix A). Spectrog ...
... main tone at approx. 19.2 kHz) and (b) a calibrated microphone in a railway station. In (a) the temporary placement of the author’s finger over the microphone (as indicated by the vertical arrows) allows the signal to be confirmed as acoustic and not electromagnetic pickup (see appendix A). Spectrog ...
Bone-Conducted Ultrasonic Hearing
... be unable to handle ultrasonic frequencies (Pumphrey, 1950). Many animals can hear much higher frequencies than 20 kHz; cats can hear over 60 kHz, dolphins can hear up to 150 MHz. Human bone-conducted ultrasonic hearing is a phenomenon in which vibrations even greater than 20 kHz are perceived by hu ...
... be unable to handle ultrasonic frequencies (Pumphrey, 1950). Many animals can hear much higher frequencies than 20 kHz; cats can hear over 60 kHz, dolphins can hear up to 150 MHz. Human bone-conducted ultrasonic hearing is a phenomenon in which vibrations even greater than 20 kHz are perceived by hu ...
Ultrasonic Hearing in Humans: Applications for Tinnitus Treatment
... A pitch-matching experiment was carried out using 10 otologically normal young adults. Each subject matched an air-conducted pure tone (variable frequency) with an ultrasonic tone of 26 or 30 kHz delivered at 5 dB SL. The mean match of five trials was tabulated for each ultrasonic frequency. The pit ...
... A pitch-matching experiment was carried out using 10 otologically normal young adults. Each subject matched an air-conducted pure tone (variable frequency) with an ultrasonic tone of 26 or 30 kHz delivered at 5 dB SL. The mean match of five trials was tabulated for each ultrasonic frequency. The pit ...
Sound - Free Exam Papers
... Any sound above 85 dB can damage hearing. You know you are listening to 85 dB sound if you have to raise your voice to be heard. ...
... Any sound above 85 dB can damage hearing. You know you are listening to 85 dB sound if you have to raise your voice to be heard. ...
Sound
... Resonant frequency of middle ear 700-1500Hz High frequency is sensed by initial portion of inner ear Low frequency is sensed by end portion Resolution of ear is very high (about 3Hz) ...
... Resonant frequency of middle ear 700-1500Hz High frequency is sensed by initial portion of inner ear Low frequency is sensed by end portion Resolution of ear is very high (about 3Hz) ...
Year: 7 Module 5 Topic: Sound waves
... Describe how developmental and environmental factors can affect hearing Ultrasound Link examples of ultrasound and infrasound to their sources/uses and Describe examples of how humans and animals use ultrasound Infrasound Explain why animals can detect sounds which humans cannot Uses of Describe how ...
... Describe how developmental and environmental factors can affect hearing Ultrasound Link examples of ultrasound and infrasound to their sources/uses and Describe examples of how humans and animals use ultrasound Infrasound Explain why animals can detect sounds which humans cannot Uses of Describe how ...
Hearing Sound
... Sound is energy that travels as longitudinal waves containing regions of high and low pressure. The audible region of the sound spectrum for humans extends from about 16 Hz - 20 kHz. ...
... Sound is energy that travels as longitudinal waves containing regions of high and low pressure. The audible region of the sound spectrum for humans extends from about 16 Hz - 20 kHz. ...
Ultrasound
Ultrasounds are sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from 'normal' (audible) sound in its physical properties, only in that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz (20,000 hertz) in healthy, young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and to accelerate chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. Scientist are also studying ultrasound using graphene diaphragms as a method of communication.