Hifiguide

Sound is a mechanical vibration that travels through matter, wether solid, liquid or gaseous. Sound travels anywhere but not in space, which is void of any matter. A sound wave consists of successive compressions and expansions of matter, mainly air.

A transducer converts information in an energy form into another energy form, be it mechanical, electrical, thermal, etc. Hence, a microphone is a mechanical to electrical transducer, a loudspeaker is an electrical to mechanical transducers, among others. Some transducer types are widespread in the sound recording domain. Here is a summary of a few.

What is a microphone ?

A microphone transforms variations in air pressure ( sound ) into mechanical vibrations and then into an electrical signal.

In a human being, sound is captured by the ear and sent to the brains as nerve ( electrical ) signals. It is the biological equivalent to a microphone. 

What is Safe Listening ?

Medias and health care practicioners talk regularily about hearing loss caused by excessively loud noises or listening to music at high volume. State authorities in charge of health and safety in the workplace have define acceptable levels, and especially the duration of sound exposure, since the effects of loud sound exposure cumulate with time.