Sound Technology Topics

Sound technology covers the capture, processing, storage and reproduction of audio, drawing on the physics of acoustics and on electronic engineering. Sound itself is a pressure wave that travels through air at roughly 343 metres per second at room temperature. Two properties dominate how a wave is perceived: its frequency, measured in hertz, which the ear interprets as pitch, and its amplitude, which relates to loudness. The audible range runs from about 20 Hz to 20 kHz for a typical young listener.

Levels and ratios in audio are expressed in decibels, a logarithmic unit suited to the wide range of intensities the ear handles. Because a decibel describes a ratio, related units such as dBm (referenced to one milliwatt) and dBV (referenced to one volt) fix a reference point. The signal-to-noise ratio (SNR), also given in decibels, indicates how far a wanted signal rises above background noise such as hiss or hum, and it is a primary measure of audio quality.

A complete audio system links several stages. A microphone turns acoustic pressure into an electrical signal; amplifiers raise the level; filters shape the frequency balance; and loudspeakers convert the electrical signal back into sound. Increasingly this work is done in the digital domain, where digital signal processing (DSP) equalises, mixes and times signals with precision. Multichannel formats such as Dolby Digital spread sound across several speakers, and engineers must manage bandwidth and avoid timing errors like jitter to keep the reproduction clean.

Frequently asked questions

What is the difference between frequency and pitch?

Frequency is the physical rate of vibration in hertz, while pitch is the ear's subjective sense of how high or low a sound is. Higher frequency is generally heard as higher pitch.

What does a microphone actually do?

A microphone is a transducer that converts the pressure variations of a sound wave into a corresponding electrical signal that can be amplified, recorded or processed.

Why is digital signal processing used in audio?

DSP allows precise and repeatable filtering, equalisation, mixing and timing of audio signals, and it makes multichannel formats and noise reduction practical.