Click here to purchase the entire book in PDF format. Introduction Noise can very basically be defined as anything in the audio that we don't want. There are two basic sources of noise in an audio chain, internal noise and noise from external sources. Internal noise is inherent in the equipment, we can either mask it with better gain structures (i.e. more gain earlier in the chain rather than later... You want to be almost clipping the output of your mic preamplifier and attenuating as you go through the remainder of your gear. This way, you're not boosting the noise of all previous equipment, except of course for the self-noise of the microphones) or just buy better equipment... Noise from external sources is caused by Electromagnetic Interference, also known as EMI, requires 3 simulaneous things... Source of electromagnetic noise Transmission medium in which the noise can propagate (usually a piece of wire, for example) A receiver sensitive to the noise