Frequency is defined as the number of cycles of periodic movement per unit time. The SI frequency unit is called Hertz (Hz, in honor of its inventor Heinrich Hertz). One hertz corresponds to one cycle (or complete oscillation) per second.
Example. Sound sound waves have a frequency in the range of about 20 to 20,000 Hz. This means that at any point on the path of the sound wave, pressure will fluctuate from high to low from 20 to 20,000 times per second.
In digital audio, the maximum frequency that can be correctly recreated is half the sampling frequency. Thus, with a sampling frequency of 44.1 kHz, frequencies can be recreated up to 22.05 kHz. Wave frequency refers to how many times per second a wave moves from its highest point to its lowest point and vice versa. This is usually measured in hertz (Hz) or the number of cycles per second. The frequency of the wave determines its height. High-frequency waves have a high height, and lower frequencies have a lower height. The average person can hear frequencies from 15 or 20 Hz to about 20,000 Hz (20 kHz).
The wave amplitude refers to half the distance between the highest point of the wave and its lowest. The larger the wave amplitude, the louder its volume, which is usually measured in decibels (dB). The range of decibels for human hearing is complex and depends on the frequency of the sound in question, the person’s age and listening conditions, but approximately ranges from 0 to 120 dB, with each change of 10 dB corresponding to a doubling of the perceived volume.
Absolute threshold – ATH is the volume level at which a certain sound can be detected in 50% of cases.