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Background Noise Detector

Find out how quiet your room and microphone really are. Start it and stay silent — the tool measures your noise floor in dBFS, rates it quiet / moderate / noisy, and pinpoints the culprits: mains hum (50/60 Hz), low-frequency rumble, and any dominant tone (fans, coil whine). It pauses automatically when it hears you speak.

🔒 Runs entirely in your browser. No audio is recorded, uploaded, or stored — only level statistics are computed.

Microphone

Device names appear after you grant permission once.
Idle — press Start, then stay quiet.

Measurements

Noise floor
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Current level
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Quietest
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Dominant tone
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Room verdict

Stay quiet to measure your noise floor
Rough guide (dBFS, depends on your gain): below −60 is quiet, −60 to −48 is moderate, above −48 is noisy. A clean voice recording wants the noise floor well below your speaking level — aim for at least 25–30 dB of separation.
Noise spectrum (log frequency) — tonal spikes reveal hum, rumble and whine
Noise-floor history — last ~10 seconds

Understanding Your Background Noise

Your noise floor is the level your microphone picks up when nothing is happening — the constant hiss, hum and rumble underneath everything you record. It comes from the room (HVAC, traffic, computer fans), the electrical environment (mains hum, ground loops), and the microphone and preamp themselves (self-noise). The lower your noise floor relative to your voice, the cleaner and more professional your recordings sound.

This tool measures the floor in dBFS — decibels below digital full scale. While you stay quiet it tracks the steady level and, if you start talking, it detects the jump and pauses so your voice doesn’t pollute the reading. It also runs an FFT to spot tonal noise — narrow spikes at specific frequencies that stand out from the broadband hiss — and names the usual suspects.

Common noise culprits and fixes

  • Mains hum (50 or 60 Hz + harmonics) — a sharp spike at your country’s mains frequency (60 Hz in the Americas, 50 Hz most elsewhere) usually means a ground loop, unbalanced cable, or interference. Try a different outlet, a balanced cable, or moving the mic away from power supplies and screens.
  • Low-frequency rumble (below ~120 Hz) — HVAC, traffic, footsteps, or desk vibration. Use a shock mount, a high-pass filter, and isolate the mic stand.
  • Mid/high whine — computer fans, coil whine, or hard drives. Move the mic away from the machine, or the machine away from the mic.
  • Broadband hiss with no spikes — usually mic/preamp self-noise or too much gain. A quieter mic, less gain, or getting closer (so you need less gain) all help.

How this differs from related tools

This is the quick "how noisy is my space" check with culprit identification. For a full per-condition profile (noise floor, speech level, SNR, dynamic range) use the Mic Sensitivity Analyzer; for a detailed spectral/per-band noise-floor breakdown use the Noise Floor Analyzer.

Frequently Asked Questions

What’s a good noise floor?
It depends on your gain, but as a rough guide for this dBFS reading: below −60 dBFS is quiet, −60 to −48 is moderate, above −48 is noisy. What matters most is the gap to your voice — for clean speech you want the noise floor at least 25–30 dB below your normal speaking level.
Why dBFS instead of real decibels (dB SPL)?
A browser can’t read calibrated sound-pressure levels, so this measures the digital signal level (dBFS) rather than room loudness in dB SPL. That’s exactly what you need to judge your recording chain’s noise — but it isn’t a substitute for a calibrated SPL meter measuring how loud the room is to your ears.
Why does it pause when I talk?
The noise floor is the level when you’re not making sound. If the level jumps well above the running floor, the tool assumes that’s you (or another sound) and excludes those moments from the floor statistics, so your voice doesn’t inflate the reading. Stay quiet for the most accurate result.
It detected 50/60 Hz hum — what do I do?
A spike at 50 or 60 Hz (and its harmonics like 100/120 Hz) is electrical hum, usually from a ground loop, an unbalanced cable, or interference from power supplies and screens. Try a different power outlet, a balanced (XLR) cable, a ground-loop isolator, and keeping the mic and its cable away from power adapters, laptops, and monitors.
Is the "dominant tone" always a problem?
Not necessarily — it just flags the strongest narrow-band component in your noise. If it’s well below your floor it’s harmless. If it’s prominent (a clear fan whine or hum), it’s worth chasing down because tonal noise is more noticeable and harder to mask than broadband hiss.
My floor is high but there are no spikes — why?
That’s broadband noise, typically microphone/preamp self-noise or simply too much gain amplifying hiss. Lower your input gain (and get closer so you still get a strong signal), or use a quieter microphone. The Mic Gain Level Meter helps you set gain with headroom.
Does noise suppression affect the reading?
The tool requests the raw signal with noise suppression and auto-gain off so you see the true floor. If your OS forces noise suppression that can’t be disabled, the reading will look artificially clean — turn off microphone "enhancements" in your system settings for an honest measurement.
Is any audio recorded?
No. The signal is analyzed in real time to compute level statistics and spot tonal peaks only; nothing is recorded, saved, or transmitted. The microphone is released when you press Stop or close the tab.

Related Tools

Noise Floor Analyzer
Detailed spectral / per-band noise-floor breakdown.
Mic Sensitivity Analyzer
Profile noise floor, speech level, SNR and dynamic range.
Mic Gain Level Meter
Set your input gain with peak-hold and a target zone.
Microphone Test
Quick check that your mic works: level, clipping, waveform, spectrum.
Audio Spectrum Analyzer
Full FFT spectrum analyzer with weighting and peak hold.
Hum Frequency Detector
Pinpoint 50/60 Hz mains hum and its harmonics.
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