How is an "Audio signal" categorized?

An audio signal is categorized primarily by its frequency range that is typically audible to the human ear. The correct answer indicates that audio signals extend from approximately 20 Hz up to 15,000 Hz. This range encompasses the frequencies that humans can hear, allowing for the perception of sound in music, voices, and other acoustic phenomena.

The lower limit is set at around 20 Hz, which is the threshold of human hearing for bass sounds, while the upper limit of 15,000 Hz represents the higher frequencies that the average human ear can detect. Beyond this range, sounds become less perceivable to most individuals and venture into the realms of ultrasound or inaudible frequencies.

Understanding this frequency range is crucial for professionals in audio engineering, sound design, and other electronic fields as it impacts how audio equipment is designed and how sound is manipulated for various applications. Knowing where audio signals lie within this spectrum allows technicians to properly analyze and work with sound in both practical and theoretical contexts.