Auditory illusion

An acoustic deception is in analogy with the optical illusion acoustic perception which has no real equivalent outside of our body in the form of a physical process. With the question of how the person hears and processed sounds, deals psychoacoustics. Audible Illusions can here provide guidance on how the human ear processes sound signals.

Residual and combination tones are not audible illusions.

Concealment

Due to anatomical peculiarities of the inner ear takes a man of two tones that are close to each other in terms of their frequency, but differ greatly from the volume, true only fair. The quieter is hidden. Among other things, this effect is exploited in the MPEG audio coding.

The effect becomes stronger with increasing level of the loud sound. Above the frequency of the sound louder the softer sound is more hidden than below. In extreme cases, the effect may extend over several octaves.

Shepard - scale

With Shepard scale is called an acoustic illusion, in which the listener has the impression that a scale continues to rise, although only the same melody is repeated. It was first described in 1964 by psychology professor Roger Shepard.

Tritone paradox

The tritone paradox was first discovered in 1986 by the American music psychologist Diana German. There is a perception paradox in which two successively sounding Shepard tones at a distance of a tritone by different listeners are perceived in different directions. While a listener always perceives example, the pair of tones C and F # as upwardly directed interval, another handset adopts this pair always true as a downward step. This is not dependent on whether it is music or not persons by the respective listeners. A reliable explanation for this phenomenon could not be delivered to date, however, there is evidence that the socialization and especially the melodic structure of the native language could have an influence on the reception.

Stereophony

In the stereophonic phantom sources are generated.

This makes use of that man hears with two ears and he reconstructed the location of the original signal through stereo speakers in stereo triangle from the acoustic signal. It is possible to achieve a spatial sound with only two channels. With a base width of magnification can be obtained the impression that the sound is coming from outside the area in which the speakers are placed. To achieve the effect Laufzeitstereofonie and intensity stereophony be used. By increasing the number of channels of the stereo image can be improved, including through the concomitant increase in the so-called sweet spot, the site on which you can hear the optimum ambient sound.

Franssen effect

The Franssen effect says that a man in reverberant rooms can only determine the direction of a sound source when the volume or tone changes greatly. Stay volume and sound is constant, a direction determination no longer possible and the initially perceived direction is maintained.

This can lead to acoustic illusions. Set in a somewhat reverberant room a sound in a speaker, it can also be a listener, which is located further back in this space (outside the reverberation radius ), determine the direction of the sound correctly. If now this sound fade very gently to a second speaker, so remains for this listener, the perceived direction of the first speaker, although now the other speaker is active. To the astonishment of the listeners can pull off even the speaker cables, the perceived direction remains with this speaker.

The explanation for this is that the use of the tone in the short term the direct sound from the sound at the listener predominates, so that the direction can be determined. A short time later hit wall reflections from all possible directions in the listener, which outweigh the direct sound. From this point a direction determination is no longer possible. The slow change of direction of the direct sound to the second speaker can no longer be perceived, and the auditory event remains at the site of the first speaker. Only when there is a greater change in volume or the sound, there is again a short period of time, wherein ( at least some frequency ranges ) of the direct sound is stronger than the reflection, so that the direction of the sound can be determined.

Synesthesia

Synesthetes connect different sensations. These people take for example, sounds as colors impressions true.

Visual influence

Also visual information can influence the perception of hearing, first described under the McGurk effect and then a novelty of cognitive psychology.

Tinnitus

If you suffer from tinnitus, you hear noises or individual sounds that have no external source and can be very disturbing.