What is gain staging?

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.

Why does the first stage matter most for noise?

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.

What is a good signal-to-noise ratio?

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.

Signal Chain Calculator — Cumulative Gain & Noise Analysis

Calculate cumulative gain and noise through a series of audio components.

Gain / Level

Stage gain in dB (use a negative value for loss/attenuation, e.g. −56 for a microphone)

Noise Floor

Input-referred noise floor of this stage in dBu (e.g. preamp EIN ≈ −128 dBu). Lower = quieter.

Gain / Level

Stage gain in dB (use a negative value for loss/attenuation, e.g. −56 for a microphone)

Noise Floor

Input-referred noise floor of this stage in dBu (e.g. preamp EIN ≈ −128 dBu). Lower = quieter.

Gain / Level

Stage gain in dB (use a negative value for loss/attenuation, e.g. −56 for a microphone)

Noise Floor

Input-referred noise floor of this stage in dBu (e.g. preamp EIN ≈ −128 dBu). Lower = quieter.

Gain / Level

Stage gain in dB (use a negative value for loss/attenuation, e.g. −56 for a microphone)

Noise Floor

Input-referred noise floor of this stage in dBu (e.g. preamp EIN ≈ −128 dBu). Lower = quieter.

How We Calculate This

The signal chain calculator sums the gain (in dB) through each stage to find the total gain and output level.

Noise is calculated with the Friis cascade. Each stage's input-referred noise floor is referred to the chain output by the gain of that stage and every stage after it, then all contributions are summed in linear power. This is why the earliest stage of gain — typically the preamp — dominates the result: its noise sees the most downstream amplification. (A lossy first stage such as a passive microphone sees the least, so it contributes very little.)

Total gain = sum of all stage gains (dB)

Output noise floor = 10·log₁₀( Σ 10^((nfᵢ + Gᵢ‧onward)/10) ) dBu

SNR = output signal level − output noise floor

Dynamic range = clip ceiling − output noise floor (clip ceiling = reference level + headroom target)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.