sound illusions. Sound illusions Shepard's tone in reverse
sound illusions can occur in absolutely healthy people under the influence of a stressful state, excitement, unusual conditions. In each case, psychologists find an appropriate explanation.
These may be sound barriers, or, as scientists call them, sound "mirrors", a distortion associated with various lengths sound wave. There are several well-known sound illusions that every healthy person can experience for themselves.
Hidden steps
A sound illusion called "hidden steps" was discovered by Diana Deutsch's, a professor of psychology who clearly proves that the human brain can group notes together.
To demonstrate this effect, two melodies are played, increasing and decreasing in tone, while the notes turn out to be different for human ears in perception. For example, one ear can hear, as if mixed up - first the first note of the first melody, then the second note of the second melody.
The brain of most listeners groups high and low notes together, so with different ears a person hears a decreasing, increasing sequence of sounds (in one ear) and vice versa, increasing, decreasing in the other ear.
The right-hander hears with the right ear first - an increasing tone, the left-hander - the opposite is true. From all this chaotic set of notes and tones, the brain selects a suitable melody, which our consciousness (sound perception) perceives with its help.
Increasing sequence
The discovery of the "increasing sequence" or Shepard's paradox belongs to the French composer Jean-Claude Risset, and is expressed in the fact that pairs of notes, following in a row, create an increasing sound illusion (as when pressing the keys on a piano from left to right).
In reality, there is no increase in tone, and if you run this melody an infinite number of times in a row, then a person will perceive a constant increase in tone, although this cannot be, this is a sound illusion created by the brain “on its own”.
falling bells
The sound illusion, called "falling" bells, consists in the fact that the sounds of bells heard in the recording "fall" with a decrease in pitch.
However, listening carefully, a person realizes that the tone, on the contrary, increases. That is, the initial pitch is lower than at the end.
Speeding up drums
The meaning of the illusion of "accelerating" drums is that in fact they sound the same, although it seems that the tempo is constantly increasing. Listen carefully!
Virtual hairdresser
The illusion, called "virtual barbershop" by experts, is a phenomenon of the binaural effect, and consists in the ability of a person and an animal to determine which side of them a sound source is located due to the presence of two ears that act as sound receivers (a source located in front or behind, is defined poorly and inaccurately).
Due to the fact that the sound passes to the ear located closer to its source, a shorter path, the sound waves in the ear canals have different phases (time of passage of this phase) and amplitude (strength) of sound vibrations. Therefore, the perception of sound different heights will be different. The direction to the sound source for low sounds (up to 1500 vibrations/second) is determined by the human consciousness most accurately and almost completely by the difference in the time of passage of a given phase of sound waves.
And for high sounds, due to the fact that the difference in sound strength at the right and left ears is of primary importance, the determination of the direction will be less accurate. The ability to determine the direction of sound arises due to the fact that the difference in phase and intensity of sounds perceived by the ear leads to a difference in impulses that enter the central nervous system from the right and left ear.
Matchbox
No less known to specialists is the stereo effect, a kind of sound illusion - " Matchbox". To achieve the result of its occurrence, it is necessary to close the eyes.
three notes
A paradox called "three notes" was also explored by Diana Deutsch's, in a sound recording, you can listen to several grouped notes, which each of the listeners perceives differently.
The difference lies in the fact that some perceive them as falling tones, while others perceive them as rising. This phenomenon has been known since ancient times, then it was considered the tricks of the devil.
phantom melodies
Phantom melodies is a sound illusion that can be created with the help of some melodies, consisting of fast losses, and very slightly different from each other. When melodies are played quickly, the brain is able to "select" some individual notes at speed and "compose" them into its own melody.
With the slow playing of the same composition, such a sound illusion does not arise, which is explained by the ability of the consciousness to have time to perceive all the correct parts of the losses.
An illustration of this phenomenon can be the composition Rustle of Spring, performed quickly, in which case a false melody will appear in the mind, and when performed slowly, the sound illusion disappears.
phantom words
This illusion was first demonstrated by Diane Deutsch of the University of California, San Diego. A record is like an overlapping sequence of repeated words or phrases located at different points in space.
As you listen to them, you begin to distinguish certain phrases. Although in fact there are no phrases. Your brain composes them on its own, in order to give meaning to meaningless noise.
How young we were.
As people age, they lose the ability to hear high frequencies. This sound can only be heard by those who have not yet celebrated their own majority (although there are exceptions among older people, but they are quite rare) - its frequency is 18000 Hz (by the way, your dog will definitely hear this sound).
Some teenagers set this sound as a ringtone mobile phone, so only they (and, of course, their peers) can hear the call. In some countries this sound is turned on very loudly in places where the appearance of young people is undesirable.
stonehenge
The history of the giant stones located in Stonehenge (England) is very interesting, they have an amazing ability to create sound illusions that are not acoustic mirages. The discovery and justification of this phenomenon belongs to the American researcher Stephen Waller, an archeoacoustic scientist who conducted research on the acoustics of the famous architectural ensemble built in southern England over 5,000 years ago.
If two musicians play the trumpet, standing in the center of this structure, then an amazing sound effect arises - in some places around the musicians the sounds of their playing are not heard, the observers "hear" silence. Waller explains this by saying that sound waves are reflected from the stones and absorb each other, resulting in a "magic circle" of complete silence around the musicians.
The people invited by the researcher to conduct the experiment, blindfolded, stood in the center of this circle and listened to the play of two trumpeters. Getting into the "dead" sound zone, they stopped hearing sounds, and then they said that they imagined an obstacle (in reality it was absent) between them and the trumpeters.
Sound illusions for mentally ill people
Completely different origins and explanations have sound illusions for mentally ill people. As a rule, sound illusions take the form of screams, voices and abuse, suspicious (for the patient) whispers, shots and whole cannonades, singing, orchestral music. Sometimes a patient in an obscure extraneous noise can "hear" individual conversations in which they take part. various people, sometimes he "recognizes" these voices, sometimes he hears the speech of strangers to him. These sound illusions are "invented" by the sick mind, passing off completely extraneous sound stimuli as distinct speech.
As in other cases of manifestation of illusions various types doctors try to separate sound illusions from auditory hallucinations. In the first case, there is an imaginary erroneous perception by the patient of extraneous noises, and in the second - invented imaginary sounds. In both cases, there is a unifying phenomenon - all "talks" are, as a rule, accusatory and condemning a sick person.
Rarely, there is a phenomenon in which sound illusions calm the patient and persuade him to calm down. Typically, sound illusions are amplified in noisy environments where a large number of sound and noise provokes the consciousness of the sick person to "hear" conversations. In cases of incorrect perception of sounds, the effect of sound illusion occurs.
Aristotle's illusion
Weber illusion
Cold objects appear heavier than warm objects of the same weight.
Illusion of sound contrast
The sound of the same strength against the background of quieter sounds seems louder than against the background of louder ones.
moon illusion
Müller-Schumann illusion
After repeatedly lifting a heavy load, a lighter load seems lighter than it actually is, and, conversely, after lifting a light load, a heavier one seems even heavier.
Illusion Charpentier
If you lift two of the same weight and appearance, but different in volume of an object, then a smaller one will be perceived by a person as heavier.
Shepard illusion
When the volume is increased, the tone is perceived as higher. To test this illusion for yourself, download the WAV file (56 Kb).
Bezold-Brücke effect
The effect is to change the hue of the light as its intensity changes. By increasing the intensity of relatively long-wavelength light, such as yellow-green or yellow-red, for example, it will appear not only brighter, but "more yellow". In the same way, short-wavelength light, perceived as blue-green and violet, begins to appear blue as the intensity increases.
McGurk effect
This effect is manifested in the fact that the auditory and visual information that speech carries interacts with each other and affects what we hear. In their original research, McGurk and MacDonald created conditions in which the auditory cues of a spoken syllable did not match the corresponding lip movements (McGurk & MacDonald, 1976). The subjects were shown a video of a person who repeatedly uttered syllables with the same lips. ga-ga, while the phonogram reproduced the syllables ba-ba. When the subjects closed their eyes and only listened to the soundtrack, they accurately recognized the syllables. Moreover, when they saw only the movements of the lips of the speaking person, and the soundtrack was turned off, they quite accurately identified the sounds being pronounced as ga-ga(thereby confirming that we can read lips when necessary and that perhaps we do this much more often than we think). However, when subjects were simultaneously presented with conflicting auditory and visual stimuli, they heard sounds that were not present in either of them. For example, when the subjects saw on the screen a person whose mouth articulation corresponded to the syllables ga-ga, and at the same time an acoustic signal sounded ba-ba, most of them heard a completely different sound - da-da! An interesting detail: most of the subjects did not realize the discrepancy between auditory and visual stimulations.
You can check the McGurk effect for yourself by downloading the video file (147 Kb). (Requires QuickTime Player to view)
Purkinje effect
Purkinje noticed in 1825 that the brightness of blue and red road signs in different time days is different: during the day both colors are equally bright, and at sunset the blue seems brighter than the red. At the onset of deeper twilight, the colors fade completely and, in general, begin to be perceived in gray tones. Red is perceived as black and blue as white. This phenomenon is associated with the transition from cone vision to rod vision with a decrease in illumination.
Shepard. Such a scale creates the illusion of an infinitely rising or falling tone, while in fact its pitch does not change as a whole.
Another sound illusion is also known, which can be called a generalization of Shepard's tone. In it, the sound consists of a series of superposition of harmonics according to the principle of Fibonacci numbers (1st, 2nd, 3rd, 5th, 8th, 13th, etc.). If you extract such a waveform every 9 semitones (for example: C, A-flat, E, and so on), then regardless of the initial pitch, their high-frequency components will be the same harmonically and overlap each other, creating the effect that the sound has high harmonics do not move, but stay in place. But if you play octaves, then the effect is created that the high-frequency component begins to “slowly slide” down as the octave rises.
Spectrum on a linear scale
Shepard's fret design
An acoustic illusion can be created by superimposing a series of ascending or descending sequences of sounds (see Fig. 1). In a visual form, the design looks like this: each square in the figure depicts a note. The squares, located one above the other, are one Shepard tone. Notes sounding at the same time are octaves apart. The color of each square represents the volume of the note. Purple corresponds to the smallest volume, green - to the largest. The volumes are distributed according to the normal law, where the top of the bell of the Gaussian curve is in the region of notes up to 5 octaves. Each sequence of sounds smoothly enters and smoothly fades away, so that, against the background of the sound of other sequences, it is almost impossible to catch its beginning and end without a well-developed ear for music. The described mode of Shepard with discrete sounds (notes) is called discrete Shepard fret. The illusion is more convincing if there are small pauses between notes (jerky performance, staccato, instead of continuous legato). Jean-Claude Riset subsequently created a version of Shepard's continuous pitch-changing mode called Rice's continuous mode or glissando Shepard - Rice. When performed correctly, it creates the illusion of a continuously rising or falling tone. Riese also created a similar illusion with a continuously speeding up or slowing down rhythm.
Application of the Shepard mode in music
Despite the difficulty of recreating the illusion with acoustic instruments, James Teni, who worked with Roger Shepard at Bell Labs in the early 1960s, composed a piece of music using this phenomenon called To Anna (For Ann). The work, in which the frequency of twelve computer-generated sine waves, separated by close but not equal intervals, continuously increases from the note A in the infrasonic range (beyond the threshold of hearing) to the note A in the ultrasonic range (also beyond the threshold of hearing), was subsequently arranged for twelve bowed instruments . The effect of an electronic piece consists of both the illusion of Shepard's infinitely rising tone, and of the sonic "overflows" and "flickers" caused by ultra-high frequencies on the verge of audibility, as well as the inability to focus on any one of the many simultaneously sounding tones. Shadows also proposed to rework the work, indicating the time of the entry of each instrument in such a way that the ratio of the frequencies of successive tones obeys the rule of the golden section. In this case, the tone that occurs when they sound simultaneously will coincide with the next emerging tone.
An effect reminiscent of Shepard's fret is in Fantasies and Fugues in G minor for Organ Bach. In the second third fantasies there is a descending bass line playing chords following the circle of fifths. The gradual addition of new registers to the sound of the organ creates the Shepard-like illusion of an infinitely lowering tone, when in fact the bass skips octaves. In the middle of Chopin's third etude, there are musical phrases similar to those of Shepard. In his book Godel, Escher, Bach: This endless garland (Godel, Escher, Bach: An Eternal Golden Braid) Douglas Hofstadter explains how you can use Shepard's scale at the end Endlessly Rising Canon Bach to create modulation without going up an octave. March Waters (Waters of March) Antonio Carlos Jobim have a descending
Such a scale creates the illusion of an infinitely rising or falling tone, while in fact its pitch does not change as a whole.
An acoustic illusion can be created by superimposing a series of ascending or descending sequences of sounds (see Fig. 1). In a visual form, the design looks like this: each square in the figure depicts a note. The squares, located one above the other, are one Shepard tone. Notes sounding at the same time are octaves apart. The color of each square represents the volume of the note. Purple color corresponds to the smallest volume, green - to the largest one. The volumes are distributed according to the normal law, where the top of the bell of the Gaussian curve is in the region of notes up to 5 octaves. Each sequence of sounds smoothly enters and smoothly fades away, so that against the background of the sound of other sequences it is impossible to catch its beginning and end by ear. The described mode of Shepard with discrete sounds (notes) is called discrete Shepard fret. The illusion is more convincing if there are small pauses between notes (jerky performance, staccato, instead of continuous legato). Jean-Claude Riset subsequently created a version of Shepard's continuous pitch-changing mode called Rice's continuous mode or glissando Shepard-Rice. When performed correctly, it creates the illusion of a continuously rising or falling tone. Riese also created a similar illusion with a continuously speeding up or slowing down rhythm.
Application of the Shepard mode in music
Despite the difficulty of recreating the illusion with acoustic instruments, James Teni, who worked with Roger Shepard at Bell Labs in the early 1960s, composed a piece of music using this phenomenon called To Anna (For Ann). The work, in which the frequency of twelve computer-generated sine waves, separated by close but not equal intervals, continuously increases from the note A in the infrasonic range (beyond the threshold of hearing) to the note A in the ultrasonic range (also beyond the threshold of hearing), was subsequently arranged for twelve bowed instruments . The effect of an electronic piece consists of both the illusion of Shepard's infinitely rising tone, and of the sonic "overflows" and "flickers" caused by ultra-high frequencies on the verge of audibility, as well as the inability to focus on any one of the many simultaneously sounding tones. Shadows also proposed to rework the work, indicating the time of the entry of each instrument in such a way that the ratio of the frequencies of successive tones obeys the rule of the golden section. In this case, the tone that occurs when they sound simultaneously will coincide with the next emerging tone.
An effect reminiscent of Shepard's fret is in Fantasies and Fugues in G minor for Organ Bach. In the second third fantasies there is a descending bass line playing chords following the circle of fifths. The gradual addition of new registers to the sound of the organ creates the Shepard-like illusion of an infinitely lowering tone, when in fact the bass skips octaves. In the middle of Chopin's third etude, there are musical phrases similar to those of Shepard. In his book Godel, Escher, Bach: This endless garland (Godel, Escher, Bach: An Eternal Golden Braid) Douglas Hofstadter explains how you can use Shepard's scale at the end Endlessly Rising Canon Bach to create modulation without going up an octave. March Waters (Waters of March) Antonio Carlos Jobim has a descending orchestration, reminiscent of Shepard's mode, and intended to depict the continuous flow of water into the ocean.
An independently discovered version of Shepard's fret appears at the beginning and end of the 1976 album A Day At The Races rock band Queen. The piece consists of many harmonizing electric guitar parts, following each other up the fret, so that the top notes constantly disappear and the bottom notes constantly appear. Echoes, a 23-minute song by rock band Pink Floyd, ends with Shepard's rising tone. Glissando Shepard-Rice is at the end of the song Ruled by Secrecy rock band Muse. Shepard's fret also appears in the fading piano coda Last drop (A Last Straw) from Robert Wyatt's 1974 opus Worse than ever (Rock Bottom).
An example of the use of Shepard's scale in modern culture is the video game's endless staircase sequence. Super Mario 64 (Super Mario 64) during which this illusion sounds. However, this is not a true Shepard scale, as it consists of only three notes within one octave, and the transition to the third note is not always perceived in the right direction.
Notes
Links
- Audio illusions (English)
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See what "Shepard's Tone" is in other dictionaries:
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
Shepard's tone, named after its creator Roger Shepard, is a sound produced by the superposition of sine waves whose frequencies are multiples of each other (sounds are arranged in octaves). Shepard's rising or falling tone is called ... ... Wikipedia
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