Pitch is determined by the frequency and loudness of the object.

1. Pitch is determined by frequency and loudness.

low-frequency tones give people a deep, thick and rough feeling, while high-frequency tones give people a bright, bright and sharp feeling.

2. The volume is determined by the vibration amplitude.

Volume, also known as loudness and sound intensity, refers to the human ear's subjective feeling of the intensity of the sound heard, and its objective evaluation scale is the amplitude of the sound. This feeling comes from the pressure produced by the vibration of the object, that is, the sound pressure.

when an object vibrates through different media, its vibration energy is conducted away. In order to quantify the feeling of sound into a monitorable index, people divide the sound pressure into sound pressure levels, so as to objectively express the strength of sound in decibels.

the function of sound:

1. echolocation

Generally, the hearing of blind people is more acute than that of normal people. Some blind people even make loud sounds with their tongues. When the sound waves hit the object in front and return to the ears of the blind people, the blind people can know the size and distance of the object in front. This is called echolocation. Animals such as bats and dolphins can use sound to judge the position relationship between the object in front of them and themselves.

2. Acoustic levitation

Acoustic levitation is to use the interaction between acoustic standing waves and objects to generate vertical levitation force to overcome the weight of objects, and at the same time generate horizontal positioning force to fix objects at sound pressure nodes.

acoustic levitation technology can be divided into three-axis and single-axis methods. The former excites a series of standing waves in three orthogonal directions to control the position of the object, while the latter only generates a series of standing waves in the vertical direction, and its levitation positioning force is provided by a certain mode of sound field excited by a cylindrical resonator.

3. Noise elimination

Noise elimination is a unique system, which can record nearby noises and cancel them in a special way, thus effectively improving the noisy environment.

4. Stabilize brainwaves

Robert Monroe makes songs by creating a series of overlapping and changing frequencies, so as to balance brainwaves in the cerebral hemisphere.

5. Promoting food production

Indian researchers can increase food production in rice fields by playing music, among which classical music and violin music have better effects, while rock music has a negative effect.