If your signal dips too low at any stage, noise becomes part of the audio you record! And, this is NOT GOOD!

This noise is broadly defined as system noise - it may be found in your patch bay, your signal processors, your mics and etc. Just part of the audio soundscape...and, it can (and must!) be controlled!

In the analog domain, system noise — whether it's high-end hiss, radio-frequency interference (RFI), 60 Hz ground-loop buzz, or some combination of the three — is often amplified at one or more stages, especially when the audio is being compressed or equalized!

The engineer should strive to minimize or eliminate all noise sources in any event!