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Image showing Doppler effect
The Doppler effect (or Doppler shift), is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. The relative changes in frequency can be explained as follows. When the source of the waves is moving toward the observer, each successive wave crest is emitted from a position closer to the observer than the previous wave. Therefore each wave takes slightly less time to reach the observer than the previous wave. Therefore the time between the arrival of successive wave crests at the observer is reduced, causing an increase in the frequency.
The Final Cut - Pink Floyd
Holophonics is a binaural recording system created by Hugo Zuccarelli that is based on the claim that the human auditory system acts as an interferometer. It relies on phase variance, just like stereophonic sound. The sound characteristics of holophonics are most clearly heard through headphones; though they can be effectively demonstrated with 2-channel stereo speakers, provided that they are phase-coherent. The word "holophonics" is related to "acoustic hologram".
The Final Cut used sound effects combined with advances and innovations in audio recording technology, the Holophonic system, an audio processing technique used to add an enhanced three-dimensional effect to the recordings. The technique is featured on "Get Your Filthy Hands Off My Desert", allowing the sound effect of an explosion to appear to surround the listener. Sound effects from earlier Floyd albums are also evident; the wind from Meddle (1971) is re-used, as are parts of The Dark Side of the Moon (1973), Wish You Were Here (1975), Animals (1977), and The Wall (1979).
Phantom vibration syndrome or phantom ringing is the sensation and false belief that one can feel one's mobile phone vibrating or hear it ringing, when in fact the telephone is not doing so.
Phantom ringing may be experienced while taking a shower, watching television, or using a noisy device. Humans are particularly sensitive to auditory tones between 1,000 and 6,000 hertz, and basic mobile phone ringers often fall within this range. This frequency range can generally be more difficult to locate spatially, thus allowing for potential confusion when heard from a distance. False vibrations are less well understood however, and could have psychological or neurological sources.
Cut away of a human ear.
Tinnitus is the perception of sound within the human ear (ringing of the ears) when no actual sound is present. Despite the origin of the name, "ringing" is but one of many sounds the person may perceive.
Tinnitus is not a disease, but a condition that can result from a wide range of underlying causes: neurological damage (multiple sclerosis), ear infections, oxidative stress, foreign objects in the ear, nasal allergies that prevent (or induce) fluid drain, wax build-up, and exposure to loud sounds. Withdrawal from benzodiazepines may cause tinnitus as well. Tinnitus may be an accompaniment of sensorineural hearing loss or congenital hearing loss, or it may be observed as a side effect of certain medications (ototoxic tinnitus). However, the most common cause is noise-induced hearing loss.
As tinnitus is usually a subjective phenomenon, it is difficult to measure using objective tests, such as by comparison with noise of known frequency and intensity, as in an audiometric test. The condition is often rated clinically on a simple scale from "slight" to "catastrophic" according to the practical difficulties it imposes, such as interference with sleep, quiet activities, and normal daily activities.