Physics of music, or what made Symphony

© RIA Novosti / Sergey Pathiterator in fotoracconti in the Great hall of the Moscow ConservatoryPhysics of music, or what made Symphony© RIA Novosti / Sergey Pathiterator the image Bank

Enjoying the music, we wonder where there is such a variety of sounds. But the mystery of the musical instruments you can slightly lift, if you look at this question from the point of view of physics.

Our organs of hearing perceive vibrations, that is, a periodic disturbance of particles in different environments — gaseous, liquid, solid. Imagine balls hanging in a row on a thin thread. If you raise extreme ball and let go it will push the next, and that, in turn, the next and so on. In the end, you will encounter a wave that will spread throughout the environment, in this case between the balls.

However, the molecules of air that propagate the sound, just will not do push — desired source. So, when playing a musical instrument, the performer causes the oscillation of one of its parts — pulling the string presses the key hits the drum.

Indignant «blow» the particles in the composition of the medium start to move to specific frequencies (the number of closed cycles of movement per unit time) and amplitude (maximum distance from the zero point). Waves with low frequencies are perceived as low sounds and higher as high. The perception of the vibrations of the particles of our organ of hearing is also affected by their phase, in fact, shift the graph of one wave from another.

It is important that decibels do not measure actual value and its change. Sound characteristics that can be directly measured, it is the intensity — the flow of energy per unit area. In addition to the original oscillation properties of the «vectors» of the noise (in particular, amplitude and frequency), it depends on the distance between objects and the resistance of the medium. For translation of intensity in decibels are required to use the following formula:

The volume (dB) = 10lg (intensity/reference intensity)

For reference the intensity take the value of the weakest audible sound, 10-12 W/m2. Let us try to calculate the volume of the noise, whose intensity is 0.2 W/m2:

0.2 W/m2 = 10lg (0,2/10-12) = 113 dB.

This level roughly corresponds to the sound of the drill.

Also in music there is the concept of the octave. In fact it is simply the interval in which the frequency ratio is one to two. After all, our ears are arranged so that, during simultaneous reproduction of these frequencies, they are coalesced into a single sound. For example, the piano has a few keys with notes La. The first octave has a frequency of 440 Hz, the second is 880 Hz, the third — 1760 Hz and so on. The keys to the La adjacent octaves (first and second, second and third), the sound seems to us to be harmonious. Precisely this effect is found in a musical scale where the same note repeats every octave.

© Illustration RIA Novosti . Alina Planinauta pianoPhysics of music, or what made Symphony© Illustration RIA Novosti . Alina Planinauta piano

However, the sound of musical instruments, is not «single». Due to the complexity of producing its objects any further hesitation. For example, in a piano has hammers that hit certain parts of the taut metal strings. But globalizovannosti touch of the hammer oscillations are distributed over the strings — its parts move with different frequencies. If you lightly touch the already touched by the guitar string, the sound will change but will not disappear completely, because it will be extinguished (or modified) part of the fluctuations.

© Illustration RIA Novosti . Alina Polyanionic sound in a piano,Physics of music, or what made Symphony© Illustration RIA Novosti . Alina Polyanionic sound in the piano

The word «timbre» often characterize the voice of a man. But have a timbre and musical instruments. This parameter distinguishes sounds of the same frequency and volume, but played on different instruments. The fact that the materials, design and form of the latter is different, as the structure of the vocal cords of every human being. Key in the determination of timbre are just overtones is a complex system of oscillations depend on the characteristics of the device of the musical instrument.

«For me, as a person who dedicated his life to music, to explain to her the sounds from the point of view of physics, only not quite acceptable. Our hearing is not just the Registrar of timbre, volume, pitch, is something more! The brain processes the received information according to individual circumstances — flexibility of hearing, it development, human’s ability to switch. Therefore, music schools, children are taught to perceive the sound, treat it like a painting where you can always find something deeper than the layman sees. In any case, each person hears their music puts into it its meaning, and this should be considered breaking the sound into simple «building blocks» drawn oscillatory characteristics of particles,» — says Irina Vorontsova, associate Professor of music theory at the Moscow state Conservatory named after P. I. Tchaikovsky.

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