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One of the most popular ways to record sound is RF condenser microphone (RF = radio frequency). It is used in telephones and high-fidelity recording microphones. RF condenser microphone can produce very good sound quality. It doesn’t need a big mass to be moved by the soundwave. This means that RF condenser microphone needs a separate power source.
How does sound move through matter?
Sounds is a vibration that moves wave. It moves through matter as a longitudinal wave. Sound can move through gas, liquid and solid, but certain materials propagate sounds better than others. The vibration of particles transport the sound vibrations as a wave. Some materials (mostly solids) will not do this very well. Sound has to have a medium (the matter) to move through. It can not travel through a vacuum.
The matter the sounds moves through effects the sound waves. The density and pressure (and temperature) effects the speed of sound in the matter. That means that sound moves through cold and hot air at different speeds. This is unnoticeable at short distances. If the matter is in motion when sound moves through it has an effect on the sound. For example sound moving through windy air. Depending on the direction it may attenuate more or less compared to non windy air. Also the viscosity of the matter affects how fast the sound attenuates.
By: Iiro Sivula, Janne Järvinen & Hester Verwej
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