Microphone Quality Test – Mic Levels, Noise Floor and Spectrum
A proper check before you record: levels in dBFS, your noise floor, whether anything is clipping, and a live spectrum showing what your microphone is actually picking up. If you only need to know whether your mic works, the mic test is faster. It works as a mic level test and a background noise test for any microphone, USB or built in.
Microphone quality test
- Peak—
- RMS—
- Clipping—
- Rumble—
What your browser is doing
Runs in your browser. Nothing is recorded or uploaded.
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How to test your microphone quality
- Press Start and allow microphone access. Use the mic you actually record with, through the interface you actually use.
- Speak normally, at your usual distance. Watch the peak figure — aim for −12 to −6 dBFS.
- Stop talking, press Measure noise floor and stay quiet for five seconds. Do not hold your breath; breathe normally away from the mic.
- Check the spectrum for a spike at 50 or 60 Hz — that is mains hum, and it is fixable.
- Read the browser processing panel. If anything is ON, the numbers describe the processing rather than your microphone.
What the numbers mean
- Peak −12 to −6 dBFS. The target. Loud enough to sit above the noise, with headroom so a laugh does not clip.
- Peak above −3 dBFS. Too hot. Turn the gain down — you can raise a quiet recording later, but clipping cannot be undone.
- Peak below −24 dBFS. Too quiet. You will have to raise it later, and that raises the noise floor with it.
- Any clipped samples. Gain is too high, full stop.
- Noise floor below −60 dBFS. Excellent. −55 to −45 is audible in quiet passages. Above −45 means something is making noise.
- Rumble above 40%. Low-frequency energy where speech has none — desk vibration, footsteps or air conditioning.
Fixing what you find
A spike at 50 or 60 Hz — mains hum
- Unplug the laptop charger and test again. If the hum vanishes on battery, it is the power supply, and that is the fastest diagnosis available.
- Move microphone and audio cables away from power leads. Running them parallel to a mains cable induces exactly this.
- Try a different USB port, ideally one on the machine rather than a hub or a monitor.
- If you use an interface with balanced inputs, use balanced cables — that is precisely the problem they exist to solve.
Noise floor too high
- Turn the gain down and move closer. Most high noise floors are gain compensating for distance. Halving the distance is worth far more than any amount of gain.
- Switch off air conditioning, fans and anything with a compressor while recording, and listen for your own computer's fans.
- If you are using a USB microphone through a hub, plug it directly in. Hubs are a common source of hiss.
- Soft furnishings help the room but do nothing for electrical noise — measure again after each change rather than doing everything at once.
Clipping, or levels all over the place
- Set gain so your loudest moment peaks at −6 dBFS, not your speaking voice. People get louder when they get interested.
- Check whether your interface has its own limiter or pad, and whether gain is also being applied in your operating system — doubling up is common.
- If levels drift during a session, something is applying automatic gain. Turn it off at the OS level as well as in the browser.
Rumble and handling noise
- Use a shock mount, or at minimum stop the stand touching the desk you type on.
- Apply a high-pass filter around 80 Hz when you record. Speech loses nothing; the rumble goes.
- Check whether your microphone has a built-in low-cut switch — many do and most people never use it.
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Frequently asked questions
How do I test my microphone quality?
Start the test and speak at your normal volume. Check your peak and RMS levels, the noise floor when you are silent, whether anything is clipping, and the live spectrum for hum or hiss.
How do I check my mic level and background noise?
Stay silent for a few seconds to read the noise floor, where lower is better, then speak normally to read your level. The questions below explain what counts as a good noise floor and level.
Does this show my microphone's frequency response?
No, and no browser tool honestly can. A frequency response curve needs a known reference signal — you would have to play a measured sweep through a calibrated speaker and record it, which measures the speaker and the room at least as much as the microphone. What the spectrum here shows is what your microphone is picking up right now. That is genuinely useful for finding mains hum, hiss and desk rumble, but it is not a statement about how your microphone responds across the frequency range. Anything claiming otherwise in a browser is guessing.
What is dBFS, and why not percentages?
Decibels relative to digital full scale. Zero is the loudest a sample can be before it clips, and everything real is negative. It is what every recording application shows, so the numbers here can be compared directly with what you see in Audacity, Reaper or Audition. A percentage bar looks friendlier but means nothing to anyone who records. Note that dBFS says nothing about loudness in the room — that needs a calibrated sound level meter.
What level should I be recording at?
Aim for peaks between −12 and −6 dBFS, with speech sitting around −18 dBFS RMS. That is loud enough to sit well above the noise floor and leaves headroom so a laugh or a cough does not clip. Recording closer to zero gains you nothing — you can raise the level later without penalty, but you cannot undo clipping.
What counts as a good noise floor?
Below −60 dBFS is excellent and better than most home setups manage. Below −55 is comfortably good enough to publish without noise reduction. Between −55 and −45 you will hear a hiss behind quiet passages. Above −45 something is actively making noise, and it is worth finding what rather than reaching for noise reduction, which always costs some quality.
The spectrum shows a spike at 50 or 60 Hz. What is that?
Mains hum, picked up from the electrical supply — 50 Hz in Australia, the UK and most of Europe, 60 Hz in North America. It usually means a ground loop, an unbalanced cable running near a power lead, or a cheap USB interface. Try a different USB port, move the cable away from power leads, and unplug the laptop charger as a test. If the hum disappears on battery, it is the power supply.
Why does it say my browser is processing the audio?
Because this page asks the browser to turn off echo cancellation, noise suppression and auto gain, and it checked whether that actually happened. Those requests are not guarantees. Chrome and Firefox generally honour them; Safari often does not. It matters here more than anywhere else on the site: if the browser is quietly suppressing noise and adjusting gain, every measurement on this page describes the processing rather than your microphone.
What is the rumble percentage?
The share of the picked-up energy sitting below 80 Hz. Human speech has very little content down there, so a high figure means something else — desk thumps travelling up a stand, footsteps, air conditioning, or a microphone too close to a vibrating surface. Above about 40% is worth addressing, usually with a shock mount or a high-pass filter when you record.
Is this a replacement for proper monitoring?
No. It is a check you can run in thirty seconds before recording, to catch the things that ruin a take and cannot be fixed afterwards — clipping, a noisy room, levels set far too low, or a browser quietly mangling your audio. Use it as a pre-flight check, not as a mixing tool.
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