Sound engineers need to make good sound two professional knowledge: tone

Pitch, also known as pitch, is the subjective evaluation scale of the human ear to the pitch of the sound. The pitch is mainly determined by the frequency, the higher the frequency, the higher the pitch, the lower the frequency, the lower the pitch. But tone

It also has something to do with the amplitude.

The human ear does not perceive the change of pitch in a linear way, but in a logarithmic way. In other words, the tonal perception is formed due to the relative change in frequency, that is, regardless of the original frequency, the same times

A change in the frequency of a number always produces the same perception of a change in tone to the human ear. For example, by doubling the frequency, such as from 100 Hz to 200 Hz or from 1 KHZ to 2 KHZ, the tone changes in the auditory perception

It is the same, that is, raising the so-called "octave", also known as "octave". It is precisely because the pitch change is proportional to the logarithm (or multiple) of the relative change in frequency that the curve representing the frequency is presented

In the figure, the frequency coordinates are often logarithmic scale, and the center in the graphic equalizer is often set at "1/2 octave" or "1/3 octave".

Every time a musical instrument emits a sound, this sound in addition to the fundamental frequency f0, there are harmonics that are integer multiples of f0. The tonal feel of each note is determined by f0, and the harmonics determine the timbre of the note. There are

When the amplitude of f0 is even higher than the first few harmonics (such as f1, f2, f3...) The amplitude is smaller, but f0's role in determining pitch is not diminished at all.

The human ear's perception of pitch is also influenced by amplitude. When the amplitude is large, the eardrum is stimulated and deformed, which affects the nerve's perception of the tone. In general, as loudness increases,

The human ear senses a decrease in tone, and the lower the frequency, the more it senses a decrease.