Signal Chain Calculator — Cumulative Gain & Noise Analysis

Gain staging is the process of setting optimal levels at each point in the signal chain. The goal is to keep the signal well above the noise floor of each device while staying below its clipping point, maximising the signal-to-noise ratio throughout.

In a chain of gain stages (the classic Friis case, where every stage amplifies), the first device contributes the most to overall noise because all subsequent gain amplifies its noise. More generally, it is the earliest stage of gain — usually the preamp — that dominates, since its noise sees the most downstream amplification; a lossy stage before it, such as a passive microphone, contributes far less. A noisy preamp cannot be compensated by a quiet A/D converter — the noise is already in the signal.

For professional recording, an SNR of 90 dB or better is expected. Hi-fi audio typically achieves 100+ dB. Broadcast audio requires at least 60 dB. An SNR below 50 dB will have audible noise in quiet passages.