We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure coreplatform@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Noise is often defined as unwanted sound or sounds that have an adverse effect on humans. What is sweet music for one person may be noise to someone else. Thus, noise is a psychological construct influenced both by physical and psychosocial properties.
Sound is created by the rapidly changing pressure of air molecules at the eardrum. A single tone, such as that from a tuning fork, can be depicted as a fixed wavelength sinusoidal pressure distribution across time. The number of pressure cycles per second, measured in hertz (Hz), is the basis for the sensation of pitch. A healthy young ear is sensitive to sounds between approximately 20 Hz and up to 20 kHz. The amplitude of the sine wave is perceived as loudness. To accommodate the wide dynamic power range of the human ear a logarithmic magnitude scale for sounds has been introduced. Its unit is the decibel (dB). Adding two independent sound sources of the same dB-level will yield a sum that is ≈3 dB higher than one of them alone. The subjective effect of a change in 3 dB amounts to a just perceptible change. A change of around 10 dB is needed to experience the sound as twice as loud.
The hearing threshold for pure tones is lowest in the frequency range 500–4000 Hz, which also is the range where human speech has its maximum energy content.
Recommend this
Email your librarian or administrator to recommend adding this to your organisation's collection.