48Hz

48Hz refers to a specific frequency of 48 hertz, meaning 48 cycles per second. This frequency lies in the lower end of the audible spectrum, which ranges from approximately 20Hz to 20,000Hz. While it is well below the pitch of most musical notes, 48Hz can still be perceived by many listeners as a deep, bass-heavy tone. The human ear’s sensitivity to frequencies in this range varies, with some individuals hearing it more clearly than others.

In audio production, 48kHz (48,000Hz) sampling is a widely adopted standard. Although not the same as 48Hz, the 48‑kilohertz sample rate is common in professional video, film, and music applications because it doubles 24kHz, providing a high‑precision representation of sound while remaining manageable for storage and processing. Many video codecs and digital cameras use 48kHz as the default audio recording rate for synchronisation with film and television footage.

In broadcasting and telecommunications, a modulation or carrier frequency of 48Hz may be used in narrowband radio and certain low‑frequency signal applications. The Unlicensed Audio Carrier (UAC) system, for example, sometimes utilizes 48Hz carriers for amateur radio practice.

Electromagnetic phenomena at 48Hz can arise in power supplies and electronic circuits. A simple half‑wave rectified AC mains signal, for example, can produce a fundamental envelope at 50Hz (or 60Hz in some regions) which can contain second‑harmonic components around 48Hz under specific load conditions. Engineers occasionally reference this frequency when analysing harmonic distortion in power lines.

The number 48 also appears in several technical and regulatory contexts, such as the 48Hz compliance standard for certain medical device audio warnings, or the 48‑Hz upper limit in some military hearing protection guidelines. Overall, 48Hz serves as a reference point across multiple disciplines, from acoustic design to electronic engineering, owing to its position at the border of human hearing and the seam of low‑frequency wave behaviour.