A microphone preamplifier is a sound engineering device that prepares a microphone signal to be processed by other equipment. Microphone signals are usually too weak to be transmitted to units such as mixing consoles and recording devices with adequate quality. Preamplifiers increase a microphone signal to line level (i.e. the level of signal strength required by such devices) by providing stable gain while preventing induced noise that would otherwise distort the signal. Items like consumer headphone mics and laptop mics will handle this for you, but all pro broadcast microphones will require a device like this. A preamplifier might add coloration by adding a different characteristic than the audio mixer's built-in preamplifiers. Some microphones, for example condensers, should be used in conjunction with an impedance matching preamplifier to function properly.
===Low-End Roll-off===
===Low-End Roll-off===
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In a room without proper soundproofing, low frequency rumbles may be transmitted through walls or normally noise dampening materials, and can make the noise picked up by the microphone sound muddy. Often, humans can not hear these noises, but they still have an effect by reducing the 'headroom' (range between nominal silence and the most powerful signal that can be accurately represented). Ideally to stop this, these low frequencies should be eliminated as early on in the chain as possible. If your microphone or preamp has a low-freq rolloff button or switch it will nearly always be worth using them in order to create the best quality vocals for your show.