Musical dynamics are one of the most important tools in the hands of a performer. The impact of dynamics is the most direct and strong. Any listener is clearly aware of the difference between loud and quiet sound; without hesitation, he can state the strengthening or weakening of sonority. This is due to the fact that all kinds of increases and decreases in the strength of sound, sounds of different strengths are often found in the reality around a person. Therefore, to perceive musical dynamics, to understand its meaning and meaning, almost no prior artistic experience is required.

Everyone is able to hear and perceive fairly subtle relative differences in loudness. Much less definite and accurate judgments about the absolute value of loudness. The subjective assessment of loudness may depend on the timbre, physical capabilities of the voice or choral part, the interaction of the juxtaposed nuances, the duration of the nuance, etc. Thus, a sound dominated by high overtones, the frequency of which will correspond to the maximum "sensitivity Hz), even with the same strength with a sound dominated by low overtones, will be perceived as louder; even a weak voice with a bright characteristic timbre coloring can cut through the sound of a powerful choir and be perceived as very loud; the perception of pianissimo after piano is completely different than after forte; with prolonged forte or fortissimo, the impact of these nuances is gradually lost, and vice versa, even sounds of medium strength after listening to quiet sounds for a long time seem loud.It should also be taken into account that the nuances indicated by the composer do not have the same meaning everywhere and can change depending on the form , genre, character ra, the style of the piece. Finally, the existing musical notation system cannot reflect all the shades of loudness to the same extent as, for example, the local speed is determined by the metronome.

It is clear from what has been said that the loudness gradations used in musical practice are of a relative nature. The most correct and clear only judgment about the loudness of sound and the boundaries of three qualities: "quiet", "moderate" and "loud". There are no clear boundaries between these "steps". Therefore, when performing music, the exact observance of one or another shade does not play a special role. Much more important are relative differences, relationships that do not depend on the physical strength of the voice or instrument. This relativity, the conventionality of dynamic designations naturally gives the performer a lot of scope for the manifestation of his creative initiative. Very often the performer has to “overestimate” the value of one or another dynamic indication, introduce additional shades not indicated by the author, and sometimes deviate from the nuances indicated in the text. This may be due to the acoustic conditions of the hall, quantitative and ka-. the qualitative composition of the choir, register, timbre, different composition of vowels, the role of the voice in the ensemble.

For example, experienced choir leaders, whose members do not have strong voices, try to use the subtlest piano gradations as the main nuance, so that even the mezzo forte gives the impression of the fortissimo required by the composer. Sometimes the conductor, taking into account the specific bright timbre of a choral part, changes the nuance indicated in the notes to muffle its brightness. The same thing happens when a part is written out by the composer in a register that is inconvenient for her (either too high - and then it sounds tense, or too low - then the sound is quiet). In such cases, to create a choral ensemble, the leader is forced to either decrease or increase the volume of its sound.

The choirs unite singers with different vocal abilities. The singers of each individual choral part, as a rule, do not have the same general range of sounding power and the intensity of sounding in different tessitures. During the rehearsal, it turns out that with the forte nuance, weaker voices disappear under the pressure of more powerful ones, and important elements of the musical fabric are lost for the listener in the overall sound.

Therefore, in the choir, it becomes necessary to adjust the usual performances. Here we can talk about the concept of loudness in four meanings: 1) the loudness of each voice separately; 2) loudness bone, voices in the ensemble; 3) the volume of the party; 4) the volume of the entire ensemble. Based on experience, we can say that the volume level of a voice in an ensemble (in a party) is determined by the dynamic capabilities of the weakest singer. For the rest of the party members, the forte of the weakest should serve as a standard by which they accordingly measure the strength of their voice. The strength of the sound of a separate part in the general ensemble depends on the characteristics of the presentation, texture. The forte of the leading party should be more intense than the forte of the accompaniment; forte in brighter registers should match the sound in dimmer ones; with a transparent, light texture, the forte will be different than with a dense and massive one.

Similar remarks apply to the performance of the piano nuance. The piano standard when performed together depends on the specifics of high and low male and female voices and on the skill of their owners. For example, pianissimo in the upper registers is easily performed by sopranos and tenors, but requires a lot of art from basses and altos. Therefore, in some cases, for the sake of general balance, the piano nuance is performed somewhat louder than the “ideal”, which, of course, should not lead to a coarsening of the general piano ensemble.

Some composers, well understanding the uniqueness of the ensemble dynamics and the difference between the nuance “in general” and the nuance “in the ensemble”, put forward refined, differentiated instructions. But this is quite rare. As a rule, the performer needs to adjust the nuance himself to achieve the required sonority balance.

A common drawback is the overload of the sonority of the background, associated with the loss of sound perspective, that is, the ratio between the leading and accompanying voices, between the main thematic material and the background. Sometimes conductors try to restore this relationship by increasing the volume of the thematic voice. However, this technique, which at first glance is absolutely logical and natural, does not always give the desired effect. It is much better to highlight the foreground not with the help of its emphasized strengthening, but by reducing the sonority of the second plan. Such a technique, undoubtedly more subtle, is especially appropriate in lyrical, discreet, quiet works, where the thematic voice should also sound piano (examples of this are “Winter Road”, “Birch”, “Lark” by V. Shebalin, “The Dawn Is Glimmering”, “ The Alps "by P. Chesnokov," The Nightingale "by P. Tchaikovsky," On the Old Barrow "," Lark "by Vik. Kalinnikov, etc.).

The performance of the nuance in each part is inextricably linked with the peculiarities of the choral instrumentation, with the tessitation of other parts, with the semantic meaning of individual voices and their role in the general musical development.

The loudness of the ensemble is based on the premise that the joint sound of all choral parts will be stronger than each separately. Therefore, the overall sonority depends on the number of simultaneously sounding choral voices and can change in one direction or another as a result of simply connecting or disconnecting parts.

In addition, it should be borne in mind that not all dynamic shades are indicated in the notes and that the appearance of a particular nuance in the text does not always mean that it must be executed with the same force from the very beginning to the end. On the contrary, some deviations from the main nuance often contribute to greater expressiveness of the performance. So, for example, in order to emphasize the culminating sound of a phrase, to make the phrasing convex, you need to highlight an important note with the help of "pressure", some increase in volume, and vice versa, "remove" the sonority after the climax. Often, expressiveness is achieved not so much by emphasizing the climactic note, but by facilitating, attenuating the end of the phrase.

Hans Schmidt, professor at the Vienna Conservatory, in his book On the Natural Laws of Musical Performance, formulated the rules according to which each longer note should be played louder than the shorter one. In the case when a longer note follows several short notes, he advised to make a small intermediate crescendo to it, so that the long note received the necessary sound strength. After a long note, Schmidt advised “to play as weakly as a long sound sounded in half its duration”, otherwise the immediately next sound would not closely adjoin the long one (“pour out” from it). Formulating his rules in relation to piano performance, Schmidt at the same time emphasized that “even in singing, the longer note receives the strongest accent, with the only difference that the singer in most cases shifts this accent to the middle of the long note”, 0.

A certain interdependence between the duration of the sound and its strength was noted by well-known contemporary musicians and teachers. Thus, A. Goldenweiser wrote in this regard: “If I play, say, forte without crescendo and diminuendo, with the same force the melodic line that goes in quarters, and then for some quarter I will play four sixteenths, with the same force each , then the listener gets the impression that I have played louder, since in the same unit of time he will perceive not one, but four sounds. Of course, this cannot be understood arithmetically, that is, that we must play these four sounds exactly four times quieter than the previous quarters, but, in any case, if we do not want these sixteenths to sound much louder than the rest, we must play each one is easier. "

Researchers also noted a certain dependence of the strength of sound on the rhythmic pattern: the more energetic the rhythm, the more actively it should be performed ^

how ^ Syncope, sung weaker than the note, and

before it, after it, or simultaneously with it, but in a different voice, it ceases to be syncope, that is, it loses its rhythmic and dynamic characteristics.

Performing nuances are largely associated with harmonic movement, with the alternation of musical stability and instability, with the functional role of chords in the fret. For example, if a dissonant chord is followed by a resolution, then it should be played quieter than the chord.

The direction of the melody is of considerable importance for nuance. Quite often, in performing practice, we are faced with an increase in the strength of the sound when the melody moves up and fading when it moves down. The expressiveness of this technique is due to the perception of an upward movement and upward dynamics as an increase in expression, emotional upsurge, and a decrease in dynamics and downward movement - as an emotional decline. However, such an association is not always legitimate. No less often, the downward movement of the melody should be accompanied by crescendo, and the upward movement - diminuendo, associated in the first case with an increase in massiveness, heaviness, and in the second - with relief, melting away.

Finally, live performing practice constantly reminds of the dependence of dynamics on tempo, and tempo on dynamics. Loud sound tends to be difficult to match with fast, virtuoso movement. The louder the sound, the heavier it is and therefore the more difficult it is to control it at a fast pace. Therefore, in works in which the composer demands forte or fortissimo at the same time as lightness, grace, grace, one should sometimes give up the power of sound to achieve the desired character of the music.

All this testifies to the fact that certain tempo, melodic, rhythmic, harmonic, textured features of the musical language often prompt the performer to correct the author's dynamic instructions. However, this should be done with great care. Too frequent, unjustified changes in basic nuances do not achieve the goal; they only tire and dull the listeners' perception, bring mannerism to the performance and can even make a humorous impression. "Nothing can damage a work like this, as an arbitrary nuance, since it opens up space for the fantastic whims of any vain tactical pusher who counts only on the effect", 2.

The main criterion for correct nuance is the content and form of the work, its warehouse and structure, the nature of the melody. In choral literature, there are many episodes written with a wide, juicy brushstroke, during the performance of which it is necessary

fractional nuances should be avoided. And vice versa, in works rich in colorful, bright, contrasting details, psychological moments, monotonous, monotonous dynamics can significantly impoverish the content and imaginative side of music. “In order not to lose the logic of the relationship between the power of sonorities and to create a sound palette rich in variety and colors,” wrote A. Pazovsky, “a conductor needs to feel and realize the“ through dynamics ”of the piece he performs. Like the end-to-end tempo rhythm, the palette of musical dynamics is the ups and downs of sound voltages, these are continuous contrasts, changes of dynamic nuances, strokes, shades of different strength and character, harmoniously combined into one large whole. "

Through various uses of dynamic nuances, the conductor can reveal one or another possibility of developing musical performing drama, creating a form that best matches the content of the work.

As already noted, a relatively stable loudness level can contribute to the unification of the form, and abrupt changes in loudness can be a means of its division. Therefore, with the help of certain dynamic techniques, the performer can influence the form of the composition. A very common technique of performing nuances is, for example, the dynamic opposition of repetitive motives, phrases, etc. (the first time is louder, the second time is quieter, or vice versa).

The dynamics in songs and choruses of a couplet structure is of particular importance, becoming here almost the main performing instrument of musical development. Changes in nuance in the various verses of a song bring contrast and variety to repetitive musical material and bring form to life. On the contrary, the technique of gradual amplification of the sound from the first verse to the last, or a combination of a smooth amplification with a smooth attenuation, especially often used, for example, in soldiers' and burlak songs, to a large extent unites the entire verse form into a single whole.

In principle, long-term crescendo and diminuendo are a very important means of unifying form and a powerful means of development. But both nuances make a truly convincing impression only if they are performed gradually and evenly. In order for the rise and fall of sonority to be carried out with great consistency, it is recommended to start crescendo slightly weaker than the main nuance, and diminuendo somewhat louder. G. Bülow recommended a wise rule: “Crescendo means piano, diminuendo means forte”. That is, the support for a long crescendo must be sought in a deep piano, and for an equally long diminuendo - in a rich and full forte. It is very useful for a gradual dynamic transition to conditionally divide the melodic line into a number of motives, each of which should be performed somewhat louder or quieter than the previous one. Moreover, even in episodes requiring great sound power, you must not give all of it.

Perhaps even more difficult than the gradual execution of crescendo and diminuendo is the sudden change in nuance for the performer. The performer should be able to convey vivid sound contrasts without softening them in any way. It takes a lot of skill. Very often, singers cannot immediately readjust from one nuance to another, which distorts the author's dynamic plan and artistic design of the work. The particular difficulty of such an instantaneous restructuring in singers is associated with the specificity of the singing mechanism of respiration, which allows for some inertia. To achieve distinct sound contrasts, caesura (short breathing) is usually used before changing nuances. Such a caesura, in addition, helps to avoid the "absorption" of the future nuance by the previous sonority.

The dynamics described above can be used by all performing musicians, regardless of the instrument they are playing. At the same time, the performance of dynamic shades in choral performance has a number of features due to the specifics of singing in general and choral singing in particular. It is known, for example, that *) the main reflex connection that regulates dynamic modulation of the voice is the connection between respiration and the larynx. The change in voice volume occurs mainly as a result of modulation of the subglottic pressure, which changes the vibrations of the vocal cords: the higher the air pressure, the greater the sound power. It can be said without exaggeration that the volume control in singing is breathing. Therefore, the choir conductor needs to pay special attention to developing correct breathing in the singers. Another important pattern in the singing voice is the increase in the strength of the voice with pitch. Acoustic research has proven that among singing masters, the volume of the sound rises smoothly from the lower tones of the range to the upper ones up to the extreme limits of the range; on the contrary, when moving from higher tones to lower tones, the strength of the sound decreases. These natural changes in sound volume in the upward and downward movement of the melody must be taken into account by the conductor when working on dynamic nuances. Otherwise, dynamic paints may be either exaggerated or insufficiently brightly executed. At the same time, it should be noted that the smooth increase in sound power, which is natural for the masters, requires a great sense of proportion and significant muscle training. Most singers fail to match the volume across the entire range.

A particularly common disadvantage is boosting the high tones. As a method of dealing with the forcing of high sounds, weakening of their volume and milling are used. The method of filing is very widely used in choral practice, where each singer, due to the specific conditions of collective work, is limited in the manifestation of his vocal data to the fullest: he must moderate and limit the power of his voice, giving only as much as is required to create a common collective sonority, to create choral part ensemble. The dynamics of this sonority is established and regulated by the conductor in accordance with the nature of the work being studied and his performance plan.

It is necessary to take into account one more specific point. Researchers have found that different grades of an inexperienced singer have different strengths. The strongest are the vowels a, e, oh, and the vowels and and at- weaker and. Only as a result of the work of the conductor with the singer can the difference in loudness between the vowels be eliminated. The power of sound is also related to its formation. Along with an increase in volume, there is an expansion of the sound, together with a fading - a narrowing. The entire choral sound, according to the principles of one of the best Soviet choral schools, the choir school of A. Sveshnikov, must go through a narrow sound: first narrow, then wide. It is a very common mistake when singers start singing loudly immediately after taking a breath. This is due to the fact that the singer involuntarily seeks to "widely" and "freely" use up the large supply of air that he now has. The conductor should constantly warn singers against such a habit, which has a disastrous effect on phrasing, on the direction of the musical line. It is necessary to ensure that the sound after taking the breath would not be louder than it was before it (of course, except when the change in nuances is indicated in the notes). In other cases, the main rule should be the following: when you start singing, always sing more quietly than the tone that is likely to be at the climax! Following this rule makes phrasing easier, comfortable and natural.

The same applies to the endings of musical phrases. Often, at the ends of phrases at the moment of "withdrawal", conductors require an active "release" of breathing. This active exhalation is usually accompanied by an increase in sonority, which often does not correspond to the required phrasing. I would like to note, by the way, that the ending of a sound, like its inception, has an innumerable number of dynamic gradations. The sound can fade, fade, and then the dynamic effect of milling is applied, it can cut off suddenly. It is especially difficult in the choir to quickly jointly end the end

sound, which is usually achieved by instantly holding the breath go with the help of hard consonants b, n, t, lightning-fast stopping sound.

The dynamic range of the chorus depends, as mentioned, on the breadth of the dynamic range of each singer. Practice shows that for inexperienced singers the difference in voice strength between forte and piano is very small. Most often they perform everything at approximately the same dynamic level, which usually corresponds to the sonority of mezzo forte. It is clear that the expressiveness of singing suffers from this, not to mention the harm of constant vocal tension for the singer himself. Therefore, the conductor should pay special attention to the formation of piano and pianissimo skills in choral singers. Then the boundaries of their dynamic range will expand significantly.

Wagner R. About conducting. - Russian musical newspaper. 1899. JS & 38.

3 Pazovsky A. Conductor's Notes, p. 291-292.

See, for example: Zernov V.D., Absolute measurement of sound strength, Moscow, 1909.

Designations

Loudness (relative)

There are two basic definitions of loudness in music:

Moderate loudness levels are indicated as follows:

Except signs f and p , There are also

Additional letters are used to indicate even more extreme levels of loudness and silence. f and p ... So, quite often in musical literature there are designations fff and ppp ... They have no standard names, they usually say “forte-fortissimo” and “piano-pianissimo” or “three forte” and “three pianos”.

In rare cases, with the help of additional f and p even more extreme degrees of sound strength are indicated. Thus, P. I. Tchaikovsky in his Sixth Symphony used pppppp and ffff , and D. D. Shostakovich in the Fourth Symphony - fffff .

Dynamics designations are relative, not absolute. For example, mp indicates not the exact volume level, but that this passage should be played somewhat louder than p , and somewhat quieter than mf ... Some computer sound recording programs have standard key velocity values ​​that correspond to a particular volume designation, but these values ​​are usually configurable. Below is a table of the correspondence of these designations to the sound volume levels in backgrounds and sounds.

Designation	Name	Volume level, background	Volume, sleep
fff	Forte fortissimo is the loudest	100	88
ff	Fortissimo - very loud	90	38
f	Forte - loud	80	17,1
p	Piano - quiet	50	2,2
pp	Pianissimo - very quiet	40	0,98
ppp	Piano-pianissimo is the quietest	30	0,36

Gradual changes

The terms are used to indicate a gradual change in volume crescendo(Italian crescendo), which denotes a gradual increase in sound, and diminuendo(Italian diminuendo), or decreechendo(decrescendo) - gradual weakening. In notes, they are abbreviated as cresc. and dim.(or decresc.). For the same purposes, special signs - "forks" are used. They are pairs of lines connected on one side and diverging on the other. If the lines diverge from left to right (<), это означает усиление звука, если сходятся (>) - weakening. The next piece of musical notation indicates a moderately loud beginning, then an increase in the sound and then its weakening:

Forks are usually written under the stave, but sometimes over it, especially in vocal music. They usually denote short-term changes in volume, and the signs cresc. and dim.- changes over a longer time interval.

Designations cresc. and dim. may be accompanied by additional instructions poco(rus. since- Little), poco a poco(rus. rest and rest- little by little), subito or sub.(rus. subito- suddenly), etc.

Drastic changes

Sforzando(Italian sforzando) or sforzato(sforzato) denotes a sudden sharp accent and is indicated by sf or sfz ... The sudden amplification of several sounds or a short phrase is called rinforzando(Italian rinforzando) and is denoted rinf. , rf or rfz .

Designation fp (forte piano) means "loudly, then immediately softly"; sfp (sforzando piano) indicates a sforzando followed by a piano.

Accent

Accent(Italian accento) - emphasizing individual tones or chords with a stronger emphasis. When writing, it is indicated by the sign > above or below the corresponding note (chord).

Musical terms related to dynamics

• al niente- literally "to nothing", to silence
• calando- "going down"; slowing down and lowering the volume.
• crescendo- enhancing
• decrescendo or diminuendo- lowering the volume
• marcato- emphasizing every note
• morendo- freezing (calming down and slowing down the pace)
• perdendo or perdendosi- losing strength, drooping
• più- more
• poco- Little
• poco a poco- little by little, little by little
• sotto voce- in an undertone
• subito- suddenly

History

The Renaissance composer Giovanni Gabrieli was one of the first to introduce indications of dynamic shades into musical notation, but until the end of the 18th century such designations were rarely used by composers. Bach used the terms piano, più piano and pianissimo(written in words), and we can assume that the designation ppp at that time meant pianissimo.

Notes (edit)

see also

Contemporary music notation
Music staff
Music signs
Strokes
Leagues
Music Music theory Musical notation

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See what "Dynamics (music)" is in other dictionaries:

MUSIC (from the Greek. Musike, literally. Art of the muses), an art form in which musical sounds are organized in a certain way as a means of embodying artistic images. The main elements and expressive means of music are fret (see LAD), ... ... encyclopedic Dictionary

Modern encyclopedia

- (from the Greek. musike literal. art of the muses), an art form in which the means of embodiment of artistic images are organized musical sounds in a certain way. The main elements and expressive means of music are mode, rhythm, meter, tempo, ... ... Big Encyclopedic Dictionary

Music- (Greek musike, literally the art of the muses), an art form in which musical sounds are organized in a certain way as a means of embodying artistic images. The main elements and expressive means of music are mode, rhythm, meter, ... ... Illustrated Encyclopedic Dictionary

- (gr. musike - literally: the art of the muses) a type of art that reflects reality in sound artistic images of a work or a set of works of this art, actively influencing the human psyche. Music is capable of concretely ... Encyclopedia of Cultural Studies

I Music (from the Greek musike, literally the art of the muses) is an art form that reflects reality and affects a person through meaningful and specially organized sound sequences, consisting mainly of tones ... ... Great Soviet Encyclopedia

- (Greek moysikn, from mousa muse) a kind of art that reflects reality and affects a person through meaningful and specially organized in pitch and time sound sequences, consisting mainly of tones ... ... Musical encyclopedia

Summary of a lesson on the subject of musical literacy and listening to music on the topic "Dynamic shades, their role and significance in music." King "of ballroom dancing (history of the emergence and spread of waltz)"

Author: Atamanova Lyudmila Ivanovna, teacher of MBOU DOD Children's School of Arts, Usman, Lipetsk region.
Short description: I offer you a summary of a lesson on the subject of musical literacy and listening to music for grade 1. This material will be useful for teachers of preschool children's school, working in the department of general aesthetic education. In the proposed development of the lesson, a person-centered approach is used. This work contains a presentation for clarity of the studied material. The lesson is aimed at developing students' musical abilities, expanding knowledge in the field of analyzing a musical work, and fostering musical culture.

Target: To acquaint students with the concept of "dynamics", to help understand the designation, the role of dynamic shades in music, as well as to tell about the origin and spread of waltz, its place in the rich and diverse world of music, involving children in active participation in the lesson.
Tasks:
1. Educational: to foster a sense of caring and respectful attitude to cultural heritage, to accept dance as a part of spiritual and national culture.
2. Developing: develop musical abilities: hearing, speech, memory, include creative imagination in the lesson, show maximum activity.
3. Educational: to form the ability to memorize, navigate in dynamic shades, apply them in practice. Recognize waltz among other musical genres.
Equipment: musical instrument, musical, literary and educational material, technical means.

During the classes

(Slide)
Teacher: Guys, in our very first lesson, we got acquainted with the concept of "sound". What is this?
Students: Sound is the result of vibrations of an elastic body (for example, a string, a column of air). Sounds are divided into musical and noise.
Teacher: And by their nature, sounds are quiet and loud, and no one will ever confuse them. There are two boxes in front of you. (Slide)
Teacher: Guess what sounds are hiding in them? First, write the missing letters horizontally into the cells, then mark in the frames what sounds they are: loud or quiet.

Teacher: And yet the concept of "loud" or "quiet" is very relative. For example, when you are in a good mood, you turn on the turntable at full volume, but the neighbor is in a bad mood that day, so he is indignant. This sound seems too loud for him. The same sound is perceived by us in different ways. But it can also sound differently. For example, sounds that are quiet for a trumpet are too loud for, say, a harp or guitar. Let's knock on the table: quietly - a little louder - even louder - loudly - very loud! Please note that the louder we knock, the more force we have to apply. (Slide)
Teacher: The power of sound is called loudness and is a very important property of musical sounds.
Write the definition in a notebook.
Music can be loud or quiet, it can abruptly or smoothly change from one volume to another. (Slide)
Teacher: Changing the volume of sounds in music is called dynamics.
Write the definition in a notebook
Dynamics (the Greek word dinamikos means "power") is the power of sound. Music, like human speech, is filled with many sound shades. The more of these shades, the more expressive it is. These tones are called dynamic. You never speak only loudly or only softly. The strength of the sound depends on what and how you want to say. To speak, sing or play with power means with feeling, with great enthusiasm. If you hit the keys hard, you get ...
Students: Loud!
Teacher: And if it is weak?
Students: Quiet!
Teacher: Italian words forte (loudly), piano (quiet)... What instrument will be named after these words?
Students: Piano.

Teacher: Remember these designations and write them down. (Slide)
Teacher: Now let's play. Solve the charade and fill the cells. The answer is written on the board
To the two well-known notes we add a preposition,
You will get a long and loud beep.
SIREN)

Teacher: Depict a siren with a voice. Start quietly, gradually increase the volume - the siren approaches, drives by, moves away ... The closer, the louder, the farther, the quieter. (Slide) Let's write the definitions:
(crescendo) crescendo - gradually increasing, (diminuendo) diminuendo - gradually weakening.

Homework

draw dynamic forks to these symbols:
P_________f; f_________p
Teacher: Today we got acquainted with only the main dynamic shades, but if you look at the dynamic forks, you can see that the sound will change at different points of these forks. We will talk about this in the next lesson, but now - listening to music and you will surely pay attention to the dynamic shades that will sound in it, as one of the most important means of musical expression. But, before the music starts playing, I have to tell about it. You, of course, have seen many times that music is closely related to all arts: literature, theater, cinema, and even with the visual arts: painting, architecture, sculpture. But all these arts exist without music, having a completely independent meaning. But there is a field of art that does not exist without music. What kind of art is this?
Students: Dance.

Teacher: Of course, dance. And therefore, when we say the word "dance", not only the dance figures of the dance itself, but also its characteristic music, the musical image of this dance, always appear in our consciousness. Dance, choreography is a huge and very diverse field of art. There are dances, born of one people, and became the property of many. Some only danced by the common people in villages and towns, others only in aristocratic salons, and there were also those who enjoyed the same success among the common people and in court circles.

Today we will only talk about one dance, an amazing dance! It arose on a certain national basis, but gradually became the dance of almost all the peoples of the world, appeared in a wide democratic environment, one might say, on the city and village squares, and became an absolutely universal dance. At first it was only meant to be danced. And very soon he literally permeated all areas of music, without exception. This dance has existed for more than three centuries and does not show any signs of aging. I think you have guessed what this dance is. Well, to make your answer more convincing, guess the riddle:

The whole hall sparkled brightly,
They invite everyone to the ball
I will ask you to answer,
What kind of dance is this?
Waltz!

Well, of course, a waltz, a three-beat dance (one, two, three). It is emphasized by the presentation of the accompaniment typical for waltz: in the first quarter there is a bass sound, and in the second and third quarters there are two chords that form a harmonious sounding harmony with the bass. (display of musical text)
Now listen to how this waltz will sound in the performance.
Performed by R. Bazhilin's student "Waltz"
For homework, distribute sheet music with "Waltz", where children have to arrange dynamic shades.
Teacher: Do you know how the waltz originated?

Long ago, the inhabitants of small Austrian towns and villages after work gathered on the lawns to relax. They sang, danced, briskly stamping their wooden shoes, circling and jumping: one, two, three. A violin played merrily a simple melody, the guys picked up the girls and slightly tossed them in the dance. And so this dance reached the most important city of Austria, its capital - Vienna. And the inhabitants of Vienna were all inveterate dancers. They danced both at home, and at a party, and in dance halls, and simply on the streets of the city. When the village dance "one-two-three" came to Vienna, the inhabitants of the Austrian capital looked down on him and said dismissively: "landl", which meant provincial, redneck. What a dance it is! Shoes knock, men toss women, they cry out in unison; try dancing such a dance on a smooth parquet - you will immediately slap! Is it really a joke to try? Of course not so dashing ... quieter, quieter! Don't jump like that! Movement is softer, smoother. And he is nothing, this "landler", this provincial! And the dance "Landler" has become a regular guest of all dance halls. (Slide)
Performed by F. Schubert "Landler"
Discussion related to character and dynamics
Teacher: And then this dance turned into another, which began to be called a waltz. But where did this name come from? Perhaps it is nobler than the previous one? Not at all! There is such a device - rollers, between which they flatten and roll metal plates. These two rollers are spinning all the time and pulling in the metal strip with their rotation. Doesn't the music of the dance draw you in, draws you into the whirling? So they called the new dance the word "waltzen" - spinning, rotating. (Slide)
Here is how the character of the waltz in his novel "Eugene Onegin" is described by A.S. Pushkin:
Monotonous and insane
Like a whirlwind of young life,
A noisy whirlwind is spinning a waltz,
The couple flickers after the couple.
But the waltz really became famous when composers paid attention to it. Do you know who was the first to compose waltzes? No? Then I'll tell you now. But for this, let's remember Andersen's fairy tales.
Students: Flint, Wild Swans, Thumbelina.
Teacher: Well, in which fairy tale does music play the main role?
Let me remind you that in this fairy tale the princess refused to accept gifts from the prince - a real rose and a nightingale - and to marry him. Then the prince smeared his face with soot and went to the princess's father-king to work. Towards evening, the prince made a magic pot, all hung with bells: when something was cooked in this pot, the bells called an old song.
Sounds "Ah, my dear Augustine"
Student: The tale is called "The Swineherd". (Slide)

Teacher: Well, who is Augustine?
Augustine is the name of the singer. He lived in Vienna almost four hundred years ago. He walked around the city and sang songs. Everyone loved Augustine very much, as in his company life became brighter and more cheerful. The singer became especially popular in the year of the plague epidemic. The Black Pestilence mowed people down mercilessly. But Augustine walked around the city and sang his songs. People listened to his songs and believed that the plague would soon pass. One day, returning home late in March night after a feast with friends, Augustine found himself in a cemetery and fell into a pit where the poor who died from the plague were buried. Waking up in the morning, Augustine, as if nothing had happened, got up and went into the city, telling his friends about his unusual overnight stay. After that, the singer's fame increased even more, and people believed that his music, his songs were stronger than the plague.
The song is played again.
Teacher: It's a waltz! It is possible that Augustine is one of the first musicians in the world to start composing waltzes! And how many beautiful waltzes have been written by composers in different countries! These are Russian, French and German composers. (Slide)

And now we will listen to the waltz of the German composer K.-M. Weber from the opera The Magic Shooter.
One of the earliest waltzes, the opera was created in 1821. Here you can still feel the connection with the landler, especially since the peasants dance in the opera to the uncomplicated accompaniment of village musicians right on the square.
The traditional shooting competition of hunters ends with a merry holiday. Peasants in their simple, uncomplicated clothes and rustic shoes dance slowly, smoothly in circles. And the melody is simple and artless, has a uniform rotational movement.
The waltz of K.-M. sounds. Weber from the opera "The Magic Shooter"
There is only one theme in the waltz, it sounds several times throughout the piece. Each waltz construction has 8 bars - this structure is typical for dance music. Well, we will finish our lesson with one of the most beautiful waltz in the world. It was composed by a man who at the beginning of the 20th century lived in the capital of waltzes, the city of Vienna, and received the title of "King of Waltzes" there. This is the famous Johann Strauss (there were two of them - father and son, both were famous and both famous, but the son significantly surpassed his father). (Slide)

In this lesson, we will talk about another means of conveying emotions - the speaker (volume) of the music.

We have already said that musical speech is very similar to speech in our traditional understanding. And one of the ways of expressing our emotions (besides the rate of reproduction of words) is another, no less strong - this is the volume with which we pronounce words. Gentle, affectionate words are spoken quietly, commands, indignation, threats, and calls are spoken loudly. Like the human voice, music can also "scream" and "whisper".

What do you think is common between explosives called "dynamite", the sports team "Dynamo" and tape "speakers"? They all come from one word - δύναμις [dynamis], translated from the Greek "strength". So the word "dynamics" comes from here. The shades of sound (or, in French, nuances) are called dynamic shades, and the strength of the musical sound is called dynamics.

The most common dynamic nuances, from quietest to loudest, are listed below:

• pp - Pianissimo - pianissimo - very quiet
• p - Piano - piano - quiet
• mp - Mezzo piano - mezzo piano - moderately quiet
• mf - Mezzo forte - mezzo forte - moderately loud
• f - Forte - forte - loud
• ff -Fortissimo - fortissimo - very loud

To indicate even more extreme levels of loudness, additional letters f and p are used. For example, the notation fff and ppp. They have no standard names, they usually say “forte-fortissimo” and “piano-pianissimo”, or “three forte” and “three pianos”.

The designation of dynamics is relative, not absolute. For example, mp does not indicate the exact volume level, but rather that this passage should be played somewhat louder than p and somewhat quieter than mf.

Sometimes the music itself tells you how to play. For example, how do you play a lullaby?

That's right - it's quiet. How to play the alarm?

Yes, loud.

But there are times when it is not clear from the musical notation what character the composer put into a piece of music. For this, the author writes hints in the form of dynamics icons under the musical text. Like that:

Dynamic nuances can be indicated both at the beginning and anywhere else in a piece of music.

There are two more speaker symbols that you will encounter quite often. In my opinion, they look a bit like bird beaks:

These icons indicate a gradual increase or decrease in the sound volume. So in order to sing louder - the bird opens its beak wider (<), а чтобы спеть потише – прикрывает клюв (>). These so-called “forks” appear below the musical text, as well as above it (especially above the vocal part).

In this example, a long dynamic fork (<),означает, что фрагмент нужно играть все громче и громче, пока не закончится знак крещендо.

And here the narrowing “fork” (>) under the musical phrase means that the fragment should be played quieter and quieter until the diminuendo sign ends, and the initial volume level in this example is mf (mezzo forte), and the final volume level is p (piano).

For these purposes, the verbal method is also often used. The term "" (Italian crescendo, abbreviated cresc.) Means a gradual increase in sound, and " Diminuendo"(Italian diminuendo, abbreviated dim.), Or decrescendo(decrescendo, abbreviated decresc.) - gradual weakening.

Cresc notation. and dim. may be accompanied by additional instructions:

• poco - peace - a little
• poco a poco - peace and quiet - little by little
• subito or sub. - subito - suddenly
• più - drink - more

Here are some more dynamic terms for you:

• al niente - al ninte - literally "to nothing", to silence
• calando - kalando - "falling"; slowing down and lowering the volume
• marcato - marcato - emphasizing each note
• morendo - morendo - freezing (fading and slowing down the pace)
• perdendo or perdendosi - perdendo - losing strength, dropping
• sotto voce - sotto voce - in an undertone

Well, in conclusion, I would like to draw your attention to another dynamic nuance - this is accent... In musical speech, it is perceived as a separate sharp cry.

In notes, it is indicated:

• sforzando or sforzato (sf or sfz) - sforzando or sforzato - sudden sharp accent
• forte piano (fp) - loud, then immediately quiet
• sforzando piano (sfp) - indicates a sforzando followed by a piano

Another "accent" when writing is indicated by a> sign above or below the corresponding note (chord).

And finally, here are a couple of examples where you, I hope, will be able to apply all the knowledge gained in practice:

February 18, 2016

The world of home entertainment is quite diverse and can include: watching a movie on a good home theater system; fun and addictive gameplay or listening to musical compositions. As a rule, everyone finds something of their own in this area, or combines everything at once. But whatever the goals of a person in organizing his leisure time and whatever extreme they go to - all these links are firmly connected by one simple and understandable word - "sound". Indeed, in all these cases, we will be led by the handle by the soundtrack. But this question is not so simple and trivial, especially in those cases when there is a desire to achieve high-quality sound in a room or any other conditions. For this, it is not always necessary to buy expensive hi-fi or hi-end components (although it will be very useful), but a good knowledge of physical theory is sufficient, which can eliminate most of the problems that arise for everyone who set out to get high quality voice acting.

Next, we will consider the theory of sound and acoustics from the point of view of physics. In this case, I will try to make it as accessible as possible for the understanding of any person who, perhaps, is far from knowing physical laws or formulas, but nevertheless passionately dreams of making the dream of creating a perfect speaker system come true. I do not presume that in order to achieve good results in this area at home (or in a car, for example), you need to know these theories thoroughly, but understanding the basics will avoid many stupid and absurd mistakes, and will also allow you to achieve the maximum sound effect from the system. any level.

General sound theory and musical terminology

What is sound? This is the sensation that the auditory organ perceives. "ear"(in itself, the phenomenon exists without the participation of the "ear" in the process, but it is easier to understand) that occurs when the eardrum is excited by a sound wave. The ear in this case acts as a "receiver" of sound waves of various frequencies.
Sound wave it is essentially a sequential series of seals and discharges of the medium (most often the air medium under normal conditions) of various frequencies. The nature of sound waves is vibrational, caused and produced by the vibration of any body. The emergence and propagation of a classical sound wave is possible in three elastic media: gaseous, liquid and solid. When a sound wave occurs in one of these types of space, some changes inevitably occur in the environment itself, for example, a change in the density or pressure of air, the movement of particles of air masses, etc.

Since a sound wave has an oscillatory nature, it has such a characteristic as frequency. Frequency measured in hertz (in honor of the German physicist Heinrich Rudolf Hertz), and denotes the number of oscillations over a period of time equal to one second. Those. for example, a frequency of 20 Hz denotes a cycle of 20 oscillations in one second. The subjective concept of its height also depends on the frequency of the sound. The more sound vibrations are made per second, the "higher" the sound seems. The sound wave also has one more important characteristic, which has a name - wavelength. Wavelength it is customary to consider the distance that a sound of a certain frequency travels in a period equal to one second. For example, the wavelength of the lowest sound in the audible range for a human being at 20 Hz is 16.5 meters, and the wavelength of the highest sound 20,000 Hz is 1.7 centimeters.

The human ear is designed in such a way that it is able to perceive waves only in a limited range, approximately 20 Hz - 20,000 Hz (depending on the characteristics of a particular person, someone is able to hear a little more, someone less). Thus, this does not mean that sounds below or above these frequencies do not exist, they are simply not perceived by the human ear, going beyond the boundaries of the audible range. The sound above the audible range is called ultrasound, the sound below the audible range is called infrasound... Some animals are able to perceive ultra and infra sounds, some even use this range for orientation in space (bats, dolphins). If the sound passes through a medium that is not in direct contact with the human hearing organ, then such a sound may not be heard or greatly weakened later.

In the musical terminology of sound, there are such important designations as the octave, tone and overtone of a sound. Octave means an interval in which the frequency ratio between sounds is 1 to 2. The octave is usually very audible, while sounds within this interval can be very similar to each other. An octave can also be called a sound that vibrates twice as much as another sound in the same time period. For example, 800 Hz is nothing more than a higher octave of 400 Hz, and 400 Hz in turn is the next octave of 200 Hz sound. The octave, in turn, consists of tones and overtones. Variable vibrations in a harmonic sound wave of one frequency are perceived by the human ear as musical tone... High-frequency vibrations can be interpreted as high-pitched sounds, low-frequency vibrations as low-pitched sounds. The human ear is able to clearly distinguish sounds with a difference of one tone (up to 4000 Hz). Despite this, the music uses an extremely small number of tones. This is explained from considerations of the principle of harmonic consonance, everything is based on the principle of octaves.

Consider the theory of musical tones using the example of a string stretched in a certain way. Such a string, depending on the tension force, will have a "tuning" to any one specific frequency. When this string is influenced by something with one definite force, which will cause it to vibrate, one definite tone of sound will be observed stably, we will hear the desired tuning frequency. This sound is called the root tone. The frequency of the "A" note of the first octave, equal to 440 Hz, is officially accepted as the fundamental tone in the musical sphere. However, most musical instruments never reproduce pure basic tones; they are inevitably accompanied by overtones, called overtones... It is appropriate to recall here an important definition of musical acoustics, the concept of sound timbre. Timbre- this is a feature of musical sounds that give musical instruments and voices their unique recognizable specificity of sound, even if we compare sounds of the same pitch and volume. The timbre of each musical instrument depends on the distribution of sound energy over tones at the moment the sound appears.

Overtones form a specific coloration of the main tone, by which we can easily identify and recognize a specific instrument, as well as clearly distinguish its sound from another instrument. Overtones are of two types: harmonic and non-harmonic. Harmonic overtones by definition are multiples of the pitch frequency. On the contrary, if the overtones are not multiples and deviate noticeably from the values, then they are called inharmonic... In music, operating with non-multiple overtones is practically excluded, therefore the term is reduced to the concept of "overtone", meaning harmonic. For some instruments, for example a piano, the fundamental tone does not even have time to form; in a short period, the sound energy of the overtones increases, and then decays just as rapidly. Many instruments create the so-called "transition tone" effect, when the energy of certain overtones is maximum at a certain point in time, usually at the very beginning, but then abruptly changes and transitions to other overtones. The frequency range of each instrument can be considered separately and is usually limited to the fundamental frequencies that that particular instrument can reproduce.

In the theory of sound, there is also such a thing as NOISE. Noise- this is any sound that is created by a set of sources that are not coordinated with each other. Everyone is familiar with the noise of the foliage of trees, swaying by the wind, etc.

What does the sound volume depend on? Obviously, this phenomenon directly depends on the amount of energy carried by the sound wave. To determine the quantitative indicators of loudness, there is a concept - the intensity of sound. Sound intensity is defined as the flow of energy that has passed through some area of ​​space (for example, cm2) per unit of time (for example, per second). In normal conversation, the intensity is about 9 or 10 W / cm2. The human ear is able to perceive sounds of a fairly wide range of sensitivity, while the frequency response is heterogeneous within the sound spectrum. This is the best way to perceive the frequency range 1000 Hz - 4000 Hz, which most widely covers human speech.

Since sounds vary so much in intensity, it is more convenient to think of it as a logarithmic quantity and measure it in decibels (after the Scottish scientist Alexander Graham Bell). The lower threshold of the human ear's auditory sensitivity is 0 dB, the upper one is 120 dB, it is also called the "pain threshold". The upper limit of sensitivity is also perceived by the human ear not in the same way, but depends on a specific frequency. Low-frequency sounds must be much more intense than high-frequency sounds in order to induce a pain threshold. For example, the pain threshold at a low frequency of 31.5 Hz occurs at a sound power level of 135 dB, when at a frequency of 2000 Hz pain sensation appears at already at 112 dB. There is also the concept of sound pressure, which actually expands the usual explanation for the propagation of a sound wave in air. Sound pressure- this is a variable excess pressure arising in an elastic medium as a result of the passage of a sound wave through it.

The wave nature of sound

To better understand the sound wave generation system, imagine a classic speaker located in a tube filled with air. If the speaker makes a sharp forward movement, then the air in the immediate vicinity of the diffuser is momentarily compressed. After that, the air will expand, thereby pushing the compressed air region along the pipe.
This wave movement will subsequently be a sound when it reaches the auditory organ and "excites" the eardrum. When a sound wave occurs in the gas, excess pressure and excess density are created, and particles move at a constant speed. It is important to remember about sound waves that matter does not move with the sound wave, but only a temporary disturbance of the air masses arises.

If we imagine a piston suspended in free space on a spring and making repeated forward-backward movements, then such oscillations will be called harmonic or sinusoidal (if we represent a wave in the form of a graph, then we will get in this case the purest sinusoid with repeated dips and rises). If we imagine a speaker in a pipe (as in the example described above), performing harmonic oscillations, then at the moment the speaker moves "forward", the already known effect of air compression is obtained, and when the speaker moves "backward", the opposite effect of vacuum is obtained. In this case, a wave of alternating compression and rarefaction will propagate through the pipe. The distance along the pipe between adjacent maxima or minima (phases) will be called wavelength... If the particles vibrate parallel to the direction of propagation of the wave, then the wave is called longitudinal... If they vibrate perpendicular to the direction of propagation, then the wave is called transverse... Usually, sound waves in gases and liquids are longitudinal, but in solids, waves of both types can arise. Shear waves in solids arise from resistance to shape change. The main difference between these two types of waves is that the shear wave has the property of polarization (oscillations occur in a certain plane), while the longitudinal wave does not.

Sound speed

The speed of sound directly depends on the characteristics of the environment in which it propagates. It is determined (dependent) by two properties of the medium: elasticity and density of the material. The speed of sound in solids, respectively, directly depends on the type of material and its properties. Velocity in gaseous media depends only on one type of deformation of the medium: compression-rarefaction. The change in pressure in a sound wave occurs without heat exchange with surrounding particles and is called adiabatic.
The speed of sound in a gas depends mainly on temperature - it increases with increasing temperature and decreases with decreasing temperature. Also, the speed of sound in a gaseous medium depends on the size and mass of the gas molecules themselves - the smaller the mass and size of the particles, the greater the "conductivity" of the wave and the higher the speed, respectively.

In liquid and solid media, the principle of propagation and the speed of sound are similar to how a wave propagates in air: by compression-discharge. But in these environments, in addition to the same dependence on temperature, the density of the medium and its composition / structure are quite important. The lower the density of the substance, the higher the speed of sound and vice versa. The dependence on the composition of the medium is more complicated and is determined in each specific case, taking into account the location and interaction of molecules / atoms.

Sound speed in air at t, ° C 20: 343 m / s
Sound speed in distilled water at t, ° C 20: 1481 m / s
Sound speed in steel at t, ° C 20: 5000 m / s

Standing waves and interference

When a speaker creates sound waves in a confined space, the effect of the waves bouncing off the boundaries inevitably occurs. As a result of this, most often there is interference effect- when two or more sound waves are superimposed on each other. Special cases of the phenomenon of interference are the formation of: 1) Beats of waves or 2) Standing waves. Beating waves- this is the case when the addition of waves with close frequencies and amplitudes occurs. Beat pattern: when two waves of similar frequency are superimposed on each other. At some point in time with this overlap, the amplitude peaks may be "out of phase" and the troughs "out of phase" may also be the same. This is exactly how sound beats are characterized. It is important to remember that, unlike standing waves, phase coincidences of peaks do not occur constantly, but at some time intervals. By ear, such a pattern of beats is distinguished quite clearly, and is heard as a periodic increase and decrease in volume, respectively. The mechanism of this effect is extremely simple: at the moment of coincidence of peaks, the volume rises, at the moment of coincidence of decays, the volume decreases.

Standing waves arise in the case of superposition of two waves of the same amplitude, phase and frequency, when when such waves "meet" one moves in the forward direction, and the other in the opposite direction. In a section of space (where a standing wave was formed), a picture of the overlap of two frequency amplitudes arises, with alternating maxima (so-called antinodes) and minima (so-called nodes). When this phenomenon occurs, the frequency, phase and attenuation coefficient of the wave at the point of reflection are extremely important. Unlike traveling waves, there is no energy transfer in a standing wave due to the fact that the forward and backward waves that form this wave transfer energy in equal amounts both in the forward and in the opposite directions. For a visual understanding of the occurrence of a standing wave, let's present an example from home acoustics. Let's say we have floor standing speakers in some limited space (room). After getting them to play some song with a lot of bass, let's try to change the location of the listener in the room. Thus, the listener, having got into the zone of minimum (subtraction) of the standing wave, will feel the effect of the fact that the bass has become very small, and if the listener gets into the zone of maximum (addition) frequencies, then the opposite effect of a significant increase in the bass region is obtained. In this case, the effect is observed in all octaves of the base frequency. For example, if the base frequency is 440 Hz, then the phenomenon of "addition" or "subtraction" will also be observed at frequencies of 880 Hz, 1760 Hz, 3520 Hz, etc.

The phenomenon of resonance

Most solids have their own resonance frequency. It is quite easy to understand this effect using the example of a conventional pipe open only at one end. Imagine a situation that a speaker is connected from the other end of the pipe, which can play some one constant frequency, it can also be changed later. So, the pipe has its own resonance frequency, in simple terms - this is the frequency at which the pipe "resonates" or emits its own sound. If the frequency of the speaker (as a result of adjustment) coincides with the resonance frequency of the pipe, then the effect of increasing the volume will appear several times. This is because the loudspeaker excites the vibrations of the air column in the tube with a significant amplitude until the very "resonant frequency" is found and the summation effect occurs. The phenomenon that has arisen can be described as follows: the pipe in this example "helps" the dynamics by resonating at a specific frequency, their efforts add up and "pour out" into an audible loud effect. On the example of musical instruments, this phenomenon can be easily traced, since in the design of most there are elements called resonators. It is not hard to guess what serves the purpose of boosting a certain frequency or musical tone. For example: a guitar body with a resonator in the form of a hole that mates with the volume; Flute tube design (and all tubes in general); The cylindrical shape of the drum body, which itself is a resonator of a certain frequency.

Frequency spectrum of sound and frequency response

Since in practice there are practically no waves of the same frequency, it becomes necessary to decompose the entire audio spectrum of the audible range into overtones or harmonics. For these purposes, there are graphs that display the dependence of the relative energy of sound vibrations on frequency. Such a graph is called an audio frequency spectrum graph. Frequency spectrum of sound there are two types: discrete and continuous. A discrete spectrum plot displays frequencies individually, separated by blank spaces. All sound frequencies are present in the continuous spectrum at once.
In the case of music or acoustics, the usual schedule is most often used. Frequency Response Characteristics(abbreviated as "frequency response"). This graph shows the dependence of the amplitude of sound vibrations on frequency throughout the entire frequency spectrum (20 Hz - 20 kHz). Looking at such a graph, it is easy to understand, for example, the strengths or weaknesses of a particular speaker or the speaker system as a whole, the strongest areas of energy return, frequency drops and rises, damping, as well as trace the slope of the decay.

Sound wave propagation, phase and antiphase

The process of propagation of sound waves occurs in all directions from the source. The simplest example for understanding this phenomenon is a pebble thrown into water.
From the place where the stone fell, waves begin to diverge along the surface of the water in all directions. However, let's imagine a situation using a speaker in a certain volume, let's say a closed box, which is connected to an amplifier and reproduces some kind of musical signal. It is not difficult to notice (especially if you send a powerful low frequency signal, for example, a bass drum) that the speaker makes a rapid forward movement, and then the same rapid movement backward. It remains to be understood that when the speaker moves forward, it emits a sound wave, which we hear later. But what happens when the speaker moves backward? And paradoxically, the same thing happens, the speaker makes the same sound, only it spreads in our example entirely within the volume of the box, without going beyond its limits (the box is closed). In general, in the example given above, one can observe quite a lot of interesting physical phenomena, the most significant of which is the concept of phase.

The sound wave that the speaker, being in the volume, emits in the direction of the listener, is "in phase". The backward wave, which goes into the volume of the box, will be correspondingly antiphase. It remains only to understand what these concepts mean? Signal phase Is the sound pressure level at the current time at some point in space. The phase is easiest to understand by the example of the reproduction of musical material by a conventional floor-standing stereo pair of home speaker systems. Let's imagine that two such floor-standing speakers are installed in a certain room and play. In this case, both acoustic systems reproduce a synchronous signal of variable sound pressure, while the sound pressure of one speaker is added to the sound pressure of the other speaker. A similar effect occurs due to the synchronous reproduction of the signal from the left and right speakers, respectively, in other words, the peaks and troughs of the waves emitted by the left and right speakers coincide.

Now imagine that the sound pressures are still changing in the same way (have not changed), but only now they are opposite to each other. This can happen if you connect one of the two speakers in reverse polarity ("+" cable from the amplifier to the "-" speaker terminal, and "-" cable from the amplifier to the "+" speaker terminal). In this case, the opposite signal will cause a pressure difference, which can be represented as numbers as follows: the left speaker will generate a pressure of "1 Pa", and the right speaker will generate a pressure of "minus 1 Pa". As a result, the total sound loudness at the listening position will be equal to zero. This phenomenon is called antiphase. If we consider the example in more detail for understanding, it turns out that two dynamics playing "in phase" - create the same areas of compaction and vacuum of air, which actually help each other. In the case of idealized antiphase, the area of ​​airspace compaction created by one speaker will be accompanied by the area of ​​airspace depression created by the second speaker. It looks approximately like the phenomenon of mutual synchronous damping of waves. True, in practice, the volume does not drop to zero, and we will hear a highly distorted and attenuated sound.

In the most accessible way, this phenomenon can be described as follows: two signals with the same oscillations (frequency), but shifted in time. In view of this, it is more convenient to represent these displacement phenomena using the example of an ordinary round analogue clock. Let's imagine that there are several identical round clocks hanging on the wall. When the second hands of this watch run synchronously, on one watch 30 seconds and on the other 30, then this is an example of a signal that is in phase. If the seconds hands run with an offset, but the speed is still the same, for example, on some watches 30 seconds, and on others 24 seconds, then this is a classic example of a phase shift (shift). Likewise, the phase is measured in degrees, within a virtual circle. In this case, when the signals are shifted relative to each other by 180 degrees (half the period), a classical antiphase is obtained. Often, in practice, slight phase displacements occur, which can also be determined in degrees and successfully eliminated.

Waves are flat and spherical. A plane wavefront propagates in only one direction and is rarely seen in practice. A spherical wavefront is a simple type of wave that emanates from a single point and travels in all directions. Sound waves have the property diffraction, i.e. the ability to bend around obstacles and objects. The degree of bending depends on the ratio of the sound wavelength to the size of the obstacle or hole. Diffraction also occurs when there is an obstacle in the path of sound. In this case, two scenarios are possible: 1) If the dimensions of the obstacle are much larger than the wavelength, then the sound is reflected or absorbed (depending on the degree of absorption of the material, the thickness of the obstacle, etc.), and a zone of "acoustic shadow" is formed behind the obstacle ... 2) If the dimensions of the obstacle are comparable to the wavelength or even less than it, then the sound diffracts to some extent in all directions. If a sound wave moving in one medium hits the interface with another medium (for example, an air medium with a solid medium), then three scenarios can arise: 1) the wave will be reflected from the interface 2) the wave can pass into another medium without changing direction 3) a wave can pass into another medium with a change in direction at the boundary, this is called "wave refraction".

The ratio of the excess pressure of a sound wave to the vibrational volume velocity is called the wave resistance. In simple terms, wave impedance of the medium can be called the ability to absorb sound waves or "resist" them. The reflection and transmission coefficients directly depend on the ratio of the characteristic impedances of the two media. The characteristic impedance in a gaseous medium is much lower than in water or solids. Therefore, if a sound wave in air falls on a solid object or on the surface of deep water, then the sound is either reflected from the surface or absorbed to a large extent. It depends on the thickness of the surface (water or solid) on which the desired sound wave falls. With a low thickness of a solid or liquid medium, sound waves almost completely "pass", and vice versa, with a large thickness of the medium, waves are more often reflected. In the case of reflection of sound waves, this process takes place according to the well-known physical law: "The angle of incidence is equal to the angle of reflection." In this case, when a wave from a medium with a lower density falls on the border with a medium of higher density, the phenomenon occurs refraction... It consists in bending (refraction) of a sound wave after "meeting" an obstacle, and is necessarily accompanied by a change in speed. Refraction also depends on the temperature of the environment in which the reflection occurs.

In the process of propagation of sound waves in space, a decrease in their intensity inevitably occurs, one can say attenuation of waves and attenuation of sound. In practice, it is quite simple to encounter such an effect: for example, if two people stand in a field at a certain close distance (a meter or closer) and begin to say something to each other. If you subsequently increase the distance between people (if they begin to move away from each other), the same level of conversational volume will become less and less audible. This example clearly demonstrates the phenomenon of a decrease in the intensity of sound waves. Why is this happening? The reason for this is the various processes of heat transfer, molecular interaction and internal friction of sound waves. Most often, in practice, there is a transformation of sound energy into heat. Such processes inevitably arise in any of the 3 sound propagation media and they can be characterized as absorption of sound waves.

The intensity and degree of absorption of sound waves depends on many factors, such as: pressure and temperature of the medium. Also, the absorption depends on the specific frequency of the sound. When a sound wave propagates in liquids or gases, the effect of friction between different particles, which is called viscosity, occurs. As a result of this friction at the molecular level, the process of transformation of the wave from sound to heat occurs. In other words, the higher the thermal conductivity of the medium, the lower the degree of wave absorption. Sound absorption in gaseous media also depends on pressure (atmospheric pressure changes with increasing altitude relative to sea level). As for the dependence of the degree of absorption on the frequency of sound, taking into account the above-mentioned dependences of viscosity and thermal conductivity, the higher its frequency, the higher the sound absorption. For example, at normal temperature and pressure, in air the absorption of a wave with a frequency of 5000 Hz is 3 dB / km, and the absorption of a wave with a frequency of 50,000 Hz will already be 300 dB / m.

In solid media, all of the above dependences (thermal conductivity and viscosity) are preserved, but several more conditions are added to this. They are associated with the molecular structure of solid materials, which can be different, with its own inhomogeneities. Depending on this internal solid molecular structure, the absorption of sound waves in this case can be different, and depends on the type of specific material. When sound passes through a solid, the wave undergoes a series of transformations and distortions, which most often leads to the dispersion and absorption of sound energy. At the molecular level, a dislocation effect can occur, when a sound wave causes a displacement of atomic planes, which then return to their original position. Or, the movement of dislocations leads to collisions with dislocations perpendicular to them or defects of the crystal structure, which causes their deceleration and, as a consequence, some absorption of the sound wave. However, the sound wave can resonate with these defects, which will distort the original wave. The energy of the sound wave at the moment of interaction with the elements of the molecular structure of the material is dissipated as a result of the processes of internal friction.

In I will try to make out the features of human auditory perception and some of the subtleties and features of sound propagation.