Dry rales are sounds produced by the narrowing or partial narrowing of the trachea, bronchi or fine bronchi, which impact the walls of the trachea during air inhalation or exhalation, characterized by a relatively long duration and musical addition to the breath sounds, with a higher pitch and longer duration, which can be heard during both inhalation and exhalation, and are most pronounced during exhalation. The intensity and nature of dry rales vary with the location and can increase or decrease suddenly. Dry rales occurring in the large airways above the main bronchus can be heard without a stethoscope, and wheezing can be heard. High-pitched dry rales are mainly caused by inflammation of relatively small bronchi or fine bronchi, like the sound of a flute; low-pitched dry rales, also known as snoring sounds, occur at the site of the trachea or main bronchi.