WHAT IS ACOUSTICS?
The term 'acoustics' embraces all aspects of sound: its generation, spread, reduction and reception in the spoken word, music and all other forms of audio.
Airborne sources of sound, generated in the air by a vibrating object, include:
- the human voice
- radio and television
- musical instruments
Unwanted or intrusive sound is normally referred to as 'noise'.
WHAT ARE DECIBELS?
Sound is measured by comparing the pressure wave it creates as it travels from its source with the nominal threshold of hearing pressure and then compressing the range using a logarithmic scale.
The result is the decibel scale, which starts at 0 dB – the point at which humans begin to hear sound – and progresses to 140 dB, the point at which a single short noise is likely to irreparably damage hearing. The scale enables sound levels picked up by the ear to be easily and meaningfully analysed – even a 3 dB change in sound pressure level is considered significant.
WHAT IS SOUND FREQUENCY?
The vibrations that produce individual sounds are measured in cycles per second and written in hertz (Hz) units which are termed the “frequency”. The human ear, which picks up sound from 20 Hz to 20,000 Hz, has varying sensitivities to different frequencies although the optimum range is between 1,000 Hz to 4,000 Hz
WHAT IS PITCH?
Pitch is another term for frequency.