The pitch of the sound is determined. Sounding world

“Sound characteristics” - A. in meters per second B. in seconds C. in hertz D. in meters. Sound characteristics. Answers: Frequency range of singers’ voices, Hz. Frequency of vibrations of the wings of insects and birds in flight, Hz. Lesson topic: Volume of sound Pitch of sound Timbre of sound. What characteristics does sound have? 6. What is approximately the speed of sound waves in air?

"Ultrasound" - Bats can bypass obstacles during flight. How does a person react to such fluctuations? Can there be oscillations less than 20 Hz? Galton's whistle. The use of ultrasound for cleaning. Each click lasts one to two milliseconds. The same fluctuations occur during storms in the oceans. Application of ultrasound in biology.

"Sound sound waves" - Answers. Speed of sound propagation. Task. Sounds are our constant companions. Artificial. The source of the human voice. Technical sound receivers. Speed of sound in different environments, m/s (at t= 20 C). Sound phenomena." And the crackling of the fire! The branch of physics that studies sound phenomena is called acoustics.

"Sound of sound vibrations" - Keywords lesson. 2. Oscillation frequency from 20 KHz. Sound cannot travel in a vacuum. Sound is generated by any vibrating body. Disturbances that propagate through a medium over time. Acoustic sound – elastic waves, spreading in gases, liquids and solids. 1. Inaccessible to the human ear.

“Use of ultrasound” - Experience 1. Ultrasound reduces friction on an oscillating surface. Ultrasound. Experiment 6. Ultrasound knocks out dust. Experiment 10. Experiment 7. Under the influence of ultrasound, cavitation bubbles form in liquids. Field of study: acoustics. Object of study: ultrasound. This phenomenon can be used to purify chlorinated water.

“Reflection of the sound of an echo” - A) answer: The characteristics of sound are volume, pitch and timbre. Practice problem solving skills. What comes first: do we hear thunder or see light from lightning? a) In Yugoslavia, one of the places near Kuršumlija for a long time was considered diabolical. Bullfrog cry out North America can be heard several kilometers away.

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Another quality of sound that humans can distinguish is pitch. For example, it is easy to distinguish the squeak of a mosquito from the hum of a bumblebee. The sound of a flying mosquito is called a high tone, and the hum of a bumblebee is called a low tone. Let us show with the help of experiment that pitch is an objective quality of sound and is uniquely determined by the frequency of vibrations in sound wave. Let us rotate gears of the same diameter, but having different number teeth (Fig. 25.4). By pressing a small piece of cardboard alternately against the teeth of these wheels, it can be established that the pitch of the tone increases as the frequency of vibration of the cardboard increases.

A sound corresponding to a strictly defined vibration frequency is called a tone. The quality of sound, which is determined by the frequency of vibrations, is characterized by pitch, with a higher frequency corresponding to a higher tone.

In some cases, pitch is characterized by the length of sound waves in air (§ 24.17). Indeed, from formula (24.23) for air at 0°C we obtain

From this formula it is clear that a higher tone corresponds to a shorter wavelength. When characterizing pitch by wavelength, it should be remembered that k also depends on the medium. Therefore, in

In different media, different wavelengths correspond to the same tone. It is not difficult to imagine that a longer wavelength will correspond to a medium with a higher speed of propagation of sound waves.

Besides volume and pitch, there is another quality of sound that humans can discern. The sound quality that allows you to determine the source of the sound is called timbre. So, by the timbre of the sound we know who is speaking, who is singing, or what instrument is being played. The reason for the different timbres of sound is as follows.

Each sound source creates standing waves. For example, a string vibrates as one unit and produces a specific tone, which is called the fundamental tone or first harmonic (§ 24.22). In addition, additional standing waves are formed on the string, similar to those shown in Fig. 24.22, creating additional tones of other frequencies that are multiples of the frequency of the main tone. They are called higher harmonic tones or overtones.

Each sound source has its own set of overtones with different relative loudness (with different amplitude), i.e., it has its own spectrum (24.22). This creates a characteristic shade (timbre) of its sound, allowing it to be distinguished from sounds created by other sources, even with the same pitch. Note that the purest sound corresponding to a certain tone is created by tuning forks. Therefore, they are used to reproduce sounds of a certain frequency, for example, when tuning musical instruments.

Often found complex sounds, in which individual tones cannot be distinguished. Such sounds are called noise.

Pitch depends on how often the sound sources vibrate. The higher the vibration frequency, the louder the sound. The simplest type of vibration is harmonic vibration. A pure tone is the sound of a tuning fork.

Pure tone- This is a sound that performs harmonic vibrations of the same frequency. In a musical tone, two qualities can be distinguished by sound - volume and pitch.

Sounds different sources(for example, different musical instruments, the human voice, sounds of foreign objects, etc.) together make up a set harmonic vibrations different frequencies.

The fundamental frequency is the smallest frequency of this multi-component sound, and the sound that corresponds to it and has a certain pitch is called the fundamental tone.

Overtones all other components of this multi-component sound are called (its frequency can be several times greater than the frequency of the fundamental tone).

Overtones determine timbre sound is what allows us to distinguish sounds, for example, we can very easily distinguish the sound of a TV and a washing machine, the sounds of a guitar and a drum, etc.

The pitch of sound is also measured in melah is a pitch scale that allows you to set the equality of the pitches of two sounds.

Shepard's tone (acoustic illusions) is a sound with an apparent pitch that rises and falls.

The pitch of a sound is determined by the frequency of its fundamental tone; if the frequency of the fundamental tone is higher, then the sound is louder; if the frequency of the fundamental tone is lower, then the sound will be quieter.

Sound volume

Sound volume- quality auditory sensation, which allows you to rank all sounds on a scale from quiet to loud.

Son is a unit of sound volume.

1 son is the approximate volume of a muffled conversation, and the volume of an airplane is 264 son. Sounds that are even louder will cause pain.

The volume of the sound depends on the amplitude of the vibrations; the larger it is, the louder the sound will be.

The sound pressure level is measured in bels (B) or decibels (D) - 1/10 part of a white (B), and is equal to the sound volume level, which is expressed in backgrounds.

Volumes above 180 dB can cause eardrum rupture.

Noise, loud sound, unpleasant sound have a bad effect on human health; this occurs due to the fact that the order of sounds of different volumes, pitches and timbres is disrupted.

Noise- These are sounds that contain vibrations of various frequencies.

In order for there to be a sound sensation, the sound wave must be of minimal intensity, but if the intensity exceeds the norm, then the sound will not be heard and will only cause pain.

Acoustics is a branch of physics that studies sound phenomena.

There are two types of sounds: natural and artificial.

Sound waves, like other waves, are characterized by such objective quantities as frequency, amplitude, oscillation phase, propagation speed, sound intensity and others. But, besides this, they are described by three subjective characteristics. These are sound volume, pitch and timbre.

The sensitivity of the human ear varies for different frequencies. In order to cause a sound sensation, the wave must have a certain minimum intensity, but if this intensity exceeds certain limit, the sound is not heard and only causes pain. Thus, for each oscillation frequency there is a minimum ( hearing threshold) and largest ( threshold pain ) the intensity of sound that is capable of causing a sound sensation. Figure 1 shows the dependence of the thresholds of hearing and pain on the frequency of sound. The area located between these two curves is audibility range. Longest distance between the curves falls on the frequencies to which the ear is most sensitive (1000-5000 Hz).

If sound intensity is a quantity that objectively characterizes wave process, then the subjective characteristic of sound is loudness. Loudness depends on the intensity of the sound, i.e. determined by the square of the amplitude of vibrations in the sound wave and the sensitivity of the ear ( physiological characteristics). Since the intensity of sound is , the greater the amplitude of the vibrations, the louder the sound.

Pitch- sound quality, determined by a person subjectively by ear and depending on the frequency of the sound. The higher the frequency, the higher the pitch of the sound.

Sound vibrations occurring along harmonic law, with a certain frequency, are perceived by a person as a certain musical tone. High frequency vibrations are perceived as sounds high tone, low frequency sounds - like sounds low tone. Range sound vibrations, corresponding to a doubling of the oscillation frequency, is called octave. So, for example, the tone “A” of the first octave corresponds to a frequency of 440 Hz, the tone “A” of the second octave corresponds to a frequency of 880 Hz.

Musical sounds correspond to the sounds produced by a harmoniously vibrating body.

Main tone complex musical sound called the tone corresponding to the lowest frequency that is present in the set of frequencies of this sound. Tones corresponding to other frequencies in the sound are called overtones. If the frequencies of the overtones are multiples of the frequency of the fundamental tone, then the overtones are called harmonic, and the fundamental tone with frequency is called first harmonic, overtone with the following frequency - second harmonic etc.

Musical sounds with the same fundamental tone differ in timbre, which is determined by the presence of overtones - their frequencies and amplitudes, the nature of the increase in amplitudes at the beginning of the sound and their decline at the end of the sound.

At the same pitch, the sounds produced by, for example, a violin and a piano are different timbre.

The perception of sound by the hearing organs depends on what frequencies are included in the sound wave.

Noises- these are sounds that form a continuous spectrum consisting of a set of frequencies, i.e. Noise contains vibrations of all possible frequencies.

Pitch

Pitch- a property of sound determined by a person by ear and depending mainly on its frequency, i.e., on the number of vibrations of the medium (usually air) per second that affect the eardrum. As the vibration frequency increases, the pitch of the sound increases. To a first approximation, the subjective pitch of a sound is proportional to the logarithm of frequency - according to the Weber-Fechner law. A sound that has a certain pitch is called tone in music.

Basics

Pitch is a subjective quality of auditory sensation, along with volume and timbre, which allows all sounds to be placed on a scale from low to high. For a pure tone, it depends mainly on frequency (as frequency increases, the pitch of the sound rises), but in subjective perception it also depends on its intensity - as intensity increases, the pitch of the sound seems lower. The pitch of a sound with a complex spectral composition depends on the distribution of energy along the frequency scale.

The units of pitch in music are tone, semitone, cent.

Also, the pitch of sound is measured in chalk - a scale of heights, the difference between which the listener perceives as equal. A tone with a frequency of 1 kHz and a sound pressure of 2·10−3 Pa is assigned a height of 1000 mel; in the range of 20 Hz - 9000 Hz, about 3000 mel fit. Measuring the pitch of an arbitrary sound is based on a person’s ability to establish the equality of the pitches of two sounds or their ratio (how many times one sound is higher or lower than another).

Measurement

The pitch of a sound is measured on a relative scale: octaves, within octaves - notes. An octave is a musical interval corresponding to the ratio of the frequencies of two sounds equal to 2. (That is, for a note with the same name in the next octave, the frequency, expressed in hertz, will be exactly 2 times higher than in the current octave).

Within the octave, the smallest musical interval is a semitone (the musical interval between the two nearest notes in the octave, approximately corresponding to the ratio of the frequencies of the two sounds, equal to . “Approximately”, because in nature the notes within the octave are unevenly spaced (see Pythagorean system, comma).

The correspondence of notes in octaves to specific frequencies (in hertz) is specified by standards.

Over the entire range of height values, they can be obtained using intervals between short pulses, for example, single intensity readings in discrete time t = ndt, where dt = 22.7 μs.

A sound that appears to be constantly rising or falling in pitch, a type of acoustic illusion, is called Shepard's tone.

Frequency signals of a complex spectrum without a fundamental frequency (the first harmonic in the spectrum) are called residual. The perception of the pitch of a frequency signal coincides with the perception of the pitch of a residual version of the same signal.