What Is Noise?
Noise is unwanted sound which may be hazardous to health, interfere with speech and verbal communications or is otherwise disturbing, irritating or annoying.
What Is Sound?
Sound is defined as any pressure variation in air, water or other fluid medium which may be detected by the human ear.
How Are These Characteristics Expressed?
The frequency of sound is expressed in wavelengths per second or cycles per second (CPS). It is more commonly referred to as Hertz. Low frequency noise is 250 Hertz (Hz) and below. High frequency noise is 2000 Hz and above. Mid-frequency noise falls between 250 and 2000 Hz.
The amplitude of sound is expressed in decibels (dB). This is a logarithmic compressed scale dealing in powers of 10 where small increments in dB correspond to large changes in acoustic energy.
There is a lot of frequency range.
Human can hear sound which has 20-20,000 hertz. I tested hearing range, I can hear 159~16,000
Here is simple test for hearing range
2. Sound Intensity Level(dB)
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