This article is part of a series; see Speech Reinforcement. This is a stub; more content may be added later.
The full signal path includes many different parts, and more than just sound system equipment. Each component carrying the signal in the system will affect the signal in some way, often reducing the signal-to-noise ratio (SNR), but usually not raising it. By carefully considering the SNR at each point, it is possible to greatly improve the performance of the system as a whole. There are the three signal paths of interest here:
Human speaker → microphone → mixing/processing → room speakers → room → ears
Human speaker → microphone → mixing/processing → assistive/outside listening → ears
Human speaker → microphone → mixing/processing → telephone network → ears