Equalization must be slow enough to avoid affecting the measurement of dynamic signals. For wireless microphone systems to work, we need access to clean RF (radio frequency spectrum) - this much. What is less well known or understood, is which bands or sections of spectrum are best suited to the operation of wireless microphone and in-ear monitor systems. The lower limiting frequency of a microphone is determined by its static pressure equalization system. Basically, a microphone measures the difference between its internal pressure and the ambient pressure. If the microphone was completely airtight, changes in barometric pressure and altitude would result in a static deflection of its diaphragm and, consequently, in a change of frequency response and sensitivity. To avoid this, the microphone is manufactured with a static pressure equalization channel for equalising the internal pressure with ambient pressure. For wireless microphone systems to work, we need access to clean RF. The sensitivity of a microphone is also related to its size which also affects its dynamic range. The smaller the diameter of the microphone, the higher are the frequencies it can measure. unlicensed basis, depending on the frequency band.4 Most licensed wireless microphones operate under the Part 74 rules for low power auxiliary stations (LPAS) on a secondary basis.
Since wavelength is inversely proportional to frequency, it gets progressively shorter at higher frequencies. The upper limiting frequency is linked to the size of the microphone compared with the wavelength of sound.
