The unit of pitch is Hertz (HZ), and the unit of volume is called "Decibel" (dB).

Pitch is determined by the frequency of vibration, and its unit can be understood as Hertz (HZ), a variety of different high and low sounds, that is, the height of the sound, one of the basic characteristics of the sound. Pitch and frequency are directly proportional to each other. If the frequency vibrates more times, the sound will be "higher", and vice versa.

Volume, also known as loudness and sound intensity, refers to the human ear’s subjective perception of the strength of the sound heard. Its objective evaluation scale is the amplitude of the sound. This feeling comes from the pressure generated when an object vibrates, that is, sound pressure. Objects vibrate through different media, conducting their vibration energy away.

In order to quantify the perception of sound into indicators that can be monitored, people divide sound pressure into "levels" - sound pressure levels, so that the strength of the sound can be objectively expressed.

The unit of volume, decibel, is a commonly used unit of measurement. It can be expressed as:

1. A unit representing the ratio of power quantity, which is equal to 10 times the common logarithm of the ratio of power intensity.

2. A unit representing the ratio of field quantities, equal to 20 times the common logarithm of the ratio of field strength and amplitude.

3. The unit of sound pressure level is approximately equal to the minimum division value at which the human ear can usually detect loudness differences.

Volume is related to the distance from the sound source and also to the timbre. These are easy to understand and are not difficult to feel in music practice.