Pitch (music)

The pitch (English technical term: pitch ) is next to the tone duration, loudness and timbre, one of the most noticeable characteristics of musical tones.

The American National Standards Institute defines the pitch as a property of auditory sensation "after the sounds on a musical scale can be ordered ( ANSI S1.1 ) ." Here pitches are rated in terms of a musical melody as higher or lower, but this presupposes that the audible sound frequency and clarity with respect to stable enough to distinguish it from a noise. For sine tones, it is closely related to the frequency of the sound. For complex audible sound, the perceived pitch depends largely on the frequency composition of the sound from. Normally, the pitch is to be understood as a simple characteristic of the sound, which is determined by the frequency of said periodic audible sound or its fundamental tone, with other aspects without importance. The issue is complex, especially in terms of music play harmonic and melodic relationships an essential role, which go beyond this simple model.

Audible sound, which has a tonal character, the human ear can assign a pitch sensation. A tonal character have sound signals in which the time structure repeated periodically ( eg sound of vibrating strings ). But a tonal character have also non-periodic sound signals in which narrowly defined frequency ranges are highlighted (eg wind howling or the sound of drums ).

The pitch can be represented as a frequency, but the pitch is not a purely objective physical property; it also has a psycho-acoustic component. Traditionally, it was and is a central problem and the subject of ongoing research in relation to speech synthesis and their perception about the hearing. For psychoacoustics is interesting sounds of certain frequency can be as high or as low perceived. For this purpose, a separate pitch scale is established and the perceived pitch. The perceived pitch is also referred to by the term critical band rate.

Musical pitch

The pitch of a sound is a musical parameter in the music, and can be individually assessed independently of other properties. The musical pitch perception includes a linear and a cyclical component. The linear pitch perception associated with the approximately a geometric change in the underlying oscillation frequencies, is coupled to the impression or decreasing brightness. The cyclical component expressed by the fact that the doubling or halving the frequency one octave higher or lower sounding tones are perceived as so similar that one interprets as a recurrence of what is already known. All sounds that have one or more octaves distance, we therefore summarizes in a class of sound at the same pitch class together and called them with the same name (possibly with an addition to the marking of the Oktavraums ).

Absolute and relative pitch

Usually given by the present notation an absolute ( standard ) pitch again. Origin is the International Stimmtonkonferenz of 1939 in London, on the pitch with a1 = 440 Hz was fixed. However, it deviations are common, especially in the notation of transposing musical instruments requires a precise prior agreement.

The character of a melody is independent of the absolute pitch. A melody can be moved as a whole by arbitrary intervals. The absolute pitch at which a piece of music is presented based on an individual agreement between the musicians and depends on many factors:

• In the simplest case when the singing voice determines the pitch used. The other instruments, the fit.
• For instruments with elaborate systems for votes as in the organ, piano or accordion determine this by jointly playing the pitch used. A shift is possible with them only by semitone transpose. Other musical instruments usually have a simple way to adjust continuously its mood to a limited extent to the aforementioned instruments.
• For musical purposes are consecutive or together sounding pitches " sound good ". But this is only the case if these sounds to comply with certain frequency ratios, that of musical intervals. The meaningful for musical purposes frequency ratios are summarized in scales. The name of the scale clay is then used as the name of the (relative) musical pitch. If, in addition, the frequency of a reference tone specified, each musical note, you can also assign an absolute pitch.

Absolute, relative and intonation hearing

A few people have the ability of absolute pitch, so are able to hear a tone map its Tonbezeichnung as part of a sound system, without having previously heard a different tone as a reference. Must be distinguished from the relative hearing that involves the identification of the area between two successive tones were interval. The relative hearing can be learned and trained by the most people through exercise, whereas the absolute pitch is debatable whether it can be purchased practicing or requires a special innate ability.

Another aspect of the musical ear is the ability Impurities intonation so small deviations in pitch by a predetermined value to detect. Experiments have shown that already satisfy eight hours of practice to get at the related ability of trained musicians. The perceptibility of deviations in pitch but there are limits. Also for musically well-trained people, the limit is about 3 cents, with this only holds true when it comes to sounds that are in the range of the best visibility to 500 Hz and last long enough.

Pitch blur

The pitch sensation is of a sufficient duration of the sound signal to the requirement. Even a sinusoidal acoustic signal e.g. only the duration of a half cycle has would be perceived by the human ear is not as sound but as a clicking sound with an indefinite pitch. The minimum time for energizing a discrete pitch sensation depends on the frequency. " For a sinusoidal signal of 1000 Hz, this value is about 12 ms. " Perception and evaluation runs parallel in several processing levels in the brain from which is closely intertwined with the upstream auditory system. The evaluation is carried out by means of spectral analysis of the much more complex than is technically possible. The reason for the pitch blur very short sound signals is that each pitch or Frequenzbestimmumg is fraught with inevitable inaccuracy ( " blur " ), as an absolutely accurate measurement would require an infinite duration of the sound signal. This follows from the uncertainty relation between time and frequency, as these two variables linked by a Fourier transform constitute "conjugate variables". Specifically, this means that the pitch is more indefinite, the shorter will take a tone. This results for the musical practice the useful knowledge that at ( very) short beeps intonation weaknesses interfere far less than for long.

Perceived pitch ( tonality )

The tonality is in psychoacoustics a sensation with the unit size message by which you can assign sound events in terms of their perceived pitch. In the picture on the right is shown how by means of listening tests results, the relationship between the frequency of a sine tone and the perceived pitch. For complex tones as they occur in reality this sensation sizes of psychoacoustics do not apply directly, and the deviations of the frequency scale is up to 5 kHz within the not yet perceived by the ear limits.

The perception of pitch is closely related to the physiology of the inner ear and the auditory brain. The inner ear performs a frequency analysis of the signal included. Different frequencies result in different locations of the inner ear to an excitation of nerve cells. The place to be reinforced at the excited neurons can be used to determine the pitch. The exact details of the function are still the subject of research, and there are several models of this.

• In the performance of the pitch, the composition of the clay from the root and overtones plays an important role. Since the period of the sound is important for pitch perception, the perceptible or audible portions of the harmonics determine, for example, in non- audible tone, the perceived pitch. This is in connection with the Residualton which forms the human ear from a frequency mixture. Thus, the period of a tone is only maintained if the greatest common divisor of the harmonic frequencies again maps the root. Although this rarely happens in a natural environment, but it is possible in principle. If, for example, a sound from the root and its first two harmonics and the fundamental and first overtone are inaudible, the sound of an octave and a fifth appears higher. This can be calculated with the GCD ( Greatest common divisor ). Is the root eg. 100Hz, the first two harmonics at 200 Hz and 300 Hz, the gcd of 100, 200, 300 then 100 is missing the root, the root pitch calculated from 200 and 300, which is still 100. But also lacks the first overtone, it is clear that the greatest common divisor of 300 is just 300. This effect can occur when, for example, an instrument is filtered or masked by other sounds so that certain frequencies masked or assigned to other sounds. Also play with the sensation of pitch knowledge, memory and the expectations of the listener a role. Thus, for example, would octaves always interpreted as a sound, since the gcd or the period would always result in the lowest root note in such a mix of frequencies. This can cause the brain on the basis of timbre - ie assess the weight, composition, and alteration of the overtones. The more trained or conditioned the listener to a certain sound, the more likely he shall act as multiple Tönhöhen. This is also related in cognition and perception of chords, as the timbre of the gcd with chords rarely monotonous sound events occur, as many of the first overtones would be missing, and the period would be very long. Therefore, the brain interprets these cases, multiple sounds instead of a very low tone. It is important to note that the brain is not mathematically determined exactly, it has since its tolerances. The gcd is just a mathematical tool to approximate how long the period of multiple frequencies will be.