Mic sensitivity converter
Compare mics from different spec sheets, and see how hot the signal will be at the preamp.
Sensitivity
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Sensitivity
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Mic output at that SPL
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Output voltage
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Preamp gain to reach target
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How it works
dBV = 20 × log10(mV/Pa ÷ 1000)
Output at SPL = sensitivity × 10(SPL − 94) / 20
Output at SPL = sensitivity × 10(SPL − 94) / 20
Sensitivity is the voltage a mic puts out at 94 dB SPL, which is a pressure of 1 pascal. 10 mV/Pa is −40 dBV.
A dynamic vocal mic at about 1.85 mV/Pa (−54.7 dBV) puts out about −52.4 dBu at 94 dB SPL. Reaching +4 dBu takes about 56 dB of preamp gain. A condenser at 20 mV/Pa is about 21 dB hotter, so it needs about 21 dB less gain for the same source.
Typical sensitivity ranges
| Mic type | mV/Pa | dBV |
|---|---|---|
| Passive ribbon | about 0.5–3 | about −66 to −50 |
| Dynamic (vocal / instrument) | about 1–3 | about −60 to −50 |
| Small-diaphragm condenser | about 5–20 | about −46 to −34 |
| Large-diaphragm condenser | about 10–40 | about −40 to −28 |
Rough ranges only. Always use the figure from the specific mic's spec sheet.
Field notes
- Loud sources change the picture. A kick drum or guitar cab can put 120–130 dB SPL on a close mic, 26–36 dB above the 94 dB reference. Then a hot condenser may need a pad, not more gain.
- Low-output mics and long cable runs are where preamp noise and hum show up first. Ribbons and quiet dynamics are the usual reasons people reach for an inline booster.
- Some spec sheets quote dBV re 1 V/µbar (an older reference). That figure is 20 dB lower than dBV re 1 V/Pa for the same mic, so add 20 dB before comparing.