Another sound quality, that can distinguish between people, is the pitch. For example, easily distinguished from bumble bee buzz mosquito Squeak. The sound of a flying mosquito called high tone, and the buzz of the Bumblebee is a low tone. Show through experience, that pitch is an objective audio quality and uniquely determined by the frequency of oscillations in sonic wave. We will result in rotating toothed wheels of the same diameter, But having a different number of teeth (rice. 25.4). Alternately pressing a small piece of cardboard to the teeth of these wheels, you can install, that pitch is increased with the increase of frequency of cardboard.

The sound, corresponds strictly certain frequencies of oscillations, call tone. Sound quality, which is determined by the frequency of oscillations, characterized by pitch, with greater frequency fluctuations indicates a high tone.

In some cases, the pitch is characterized by the length of the sound waves in the air. Indeed, from the formula for air at 0° c, we obtain:

λ = (332 m/s)/v. (25.2)

From this formula it is seen, that a higher tone corresponds to the shorter wavelength. Describing the pitch of a wavelength, remember, that λ still depends on Wednesday. Therefore, various Wednesday the same tone correspond to different wavelengths. It's simple to understand, that large wavelength will match Wednesday with greater speed the dissemination of sound waves.

In addition to volume and pitch, There is another sound quality, that can distinguish between people. Sound quality, that enables you to specify the source of sound, called timbre. So, on the timbre of the sound we learn, who says, who sings or what instrument played. The reason for the different timbres of sound next.

Each sound source creates standing waves. For example, string as a single unit and publishes a specific tone, which is called the basic tone or first harmonica. In addition, the string formed another incremental standing waves, such embossed, create additional tones of different frequencies, multiple frequency main tone. They are called higher harmonic tones or overtones.

Each source has its own set of overtones with varying relative loudness (with varying amplitude), t. e. has its own range of. This creates the characteristic shade (timbre) its sound, to distinguish it from the sounds, generated by other sources, even with the same basal tone. Note, that the most pure sound, corresponds to a specific tone, create tuning forks. Therefore, they are used to play sounds of a certain frequency, for example, When setting up musical instruments.

Often there are complex sounds, in which you cannot select individual tones. These sounds are called noise.