Mic test: check your microphone online

Check your mic before the interview, the episode or the call. Watch the live meter, record 8 seconds, listen back and see whether your level, noise, hum and tone are right. Free, in your browser, with no upload.

Input levelClipping

Your browser will ask to use the microphone. The audio stays in this browser unless you choose to upload it.

How the mic test works

  1. Start the mic

    Press Start mic test and allow the microphone when your browser asks. If you have more than one, pick it from the list. The bar shows your level as you talk, the grey band is where speech should sit and the light turns red when the signal clips. The bars underneath show which frequencies the mic is picking up.

  2. Record 8 seconds

    Stay quiet for the first 2 seconds so the test can hear the room on its own, then talk the way you will when it counts: the same distance from the mic, in the same voice.

  3. Listen back and read the results

    Play the recording. The test checks 4 things, all worked out in your browser with the Web Audio API: how loud you are, how much noise sits under you, whether there's electrical hum and whether the mic captures the whole voice. Each result says what to change if it isn't right.

Your audio stays here. Nothing is uploaded. The recording lives in this tab until you close it, save it as a WAV file or choose to upload it to Diffio.

How to read your mic test results

Level

Levels are in dBFS, decibels below full scale, where 0 dBFS is the loudest a digital recording can hold. Speech should peak between about -12 and -6 dBFS. Below about -24 dBFS the test says your mic is too quiet, because turning a quiet recording up later raises the noise with it. If the waveform hits its limit and flattens, the test reports clipping and counts how many times it happened.

Background noise

The test measures the room during the quiet first 2 seconds. A noise floor below -60 dBFS is quiet. Between -60 and -45 dBFS you'll hear it in the pauses. Above -45 dBFS, or less than 20 dB below your voice, it's under every word. If you talked during the quiet part, the test uses the quietest moments of the recording instead.

Mains hum

Electrical hum is a steady tone at the mains frequency: 60 Hz in the U.S. and 50 Hz in much of the world, often with more tones at 2 and 3 times that. A voice changes pitch all the time and hum doesn't, so the test looks for a sharp peak at those frequencies that holds for the whole recording.

Tone and bandwidth

A good mic captures a voice past 8 kHz, where the detail in "s", "t" and "f" lives. If the voice stops near 4 kHz, the mic is in a phone-style mode, which is what a Bluetooth headset does when its mic is on, or something is covering it. A gentler loss of the top end reads as muffled.

What the test doesn't check

Room echo depends on the room more than on the mic, and 8 seconds of talking isn't enough to measure it well. Clap once and listen: if you hear a tail after the clap, the room will be in your recording. The placement tips below help, and Diffio can reduce echo in a recording you've already made.

Common mic problems and how to fix them

Your mic is too quiet

Raise the input level where the signal starts. On Windows, open Settings > System > Sound, choose your mic under Input and raise its volume. On a Mac, open System Settings > Sound > Input. With an audio interface, turn up the gain knob rather than the volume in software. Then move closer: halving the distance to the mic makes your voice about 6 dB louder compared with the room. A recording that's already too quiet can still be rescued; see how to fix bad mic audio.

Your mic is clipping or distorted

Lower the gain until your loudest laugh peaks around -6 dBFS, or sit back a little. On Windows, also look for Microphone Boost on the Levels tab of the mic's properties and turn it down. Once a take has clipped, turning it down doesn't remove the distortion; Diffio can repair some clipped and distorted speech.

There's background noise

Turn off fans and air conditioning, close the window and move away from the computer. Getting closer to the mic helps as much as anything, since your voice gets louder and the room doesn't. A dynamic mic picks up less of the room than a condenser. For noise already in a recording, see how to remove background noise from audio.

Your mic hums or buzzes

Hum usually comes from a ground loop. Unplug the laptop charger while recording, plug the computer and the interface into the same power strip, keep mic cables away from power cords and try a different USB port. An analog mic on a long cable may need a balanced XLR cable or a ground loop isolator. Hum already in a recording can be taken out; see how to remove hum, hiss and static.

Your voice sounds muffled or thin

Make sure nothing covers the mic and that you're talking into its front. Many USB condenser mics are side-address: you talk into the side with the logo, not the top. If you're on a Bluetooth headset, switch the input to a wired, USB or built-in mic, since Bluetooth drops to a narrow call mode whenever its mic is in use.

The room echoes

Hard walls, bare floors and empty rooms reflect your voice back into the mic. Record in a room with a rug, curtains or a sofa, face into the room rather than a wall and get closer to the mic. For a recording that already sounds roomy, see how to remove reverb from audio.

Mic placement tips

  • USB and podcast mics: about a hand's width away, 4 to 8 inches (10 to 20 cm). Closer gives more voice and less room; much closer adds boom and pops.
  • Talk across the mic, not straight into it, so "p" and "b" sounds don't pop. A foam windscreen or pop filter helps too.
  • Outdoors: use a foam or furry windscreen and turn your back to the wind. Gusts hitting the mic sound like low thumps no meter warns you about until they happen. If they're already in the take, see how to remove wind noise.
  • Laptop mics: raise the laptop so the mic is near mouth height, sit no more than an arm's length away and keep your hands off the keyboard while you talk.
  • Phones: hold the phone about 8 inches (20 cm) away with the bottom edge toward you, where the main mic is, and set your voice memo app to its highest quality.
  • Headsets: put the boom mic at the corner of your mouth, about a finger's width away, so your breath doesn't hit it.
  • Lavalier mics: clip it to the middle of your chest, about a hand's width below the chin, outside your clothes so fabric doesn't rub against it.

Mic not working? Allow it in your browser and system

If the test can't start, the browser or your computer is blocking the mic, or another app is using it. Find your browser and system below.

Chrome
  1. Click the site settings icon to the left of the address, set Microphone to Allow and reload the page.
  2. If the mic is still missing, open Settings > Privacy and security > Site settings > Microphone. Pick your mic in the menu at the top and remove diffio.ai from the blocked list.
Microsoft Edge
  1. Click the lock icon to the left of the address, set Microphone to Allow and reload the page.
  2. To pick a different mic, open Settings > Cookies and site permissions > Microphone.
Safari on a Mac
  1. Choose Safari > Settings for diffio.ai and set Microphone to Allow. Reload the page.
  2. Or open Safari > Settings > Websites > Microphone and change diffio.ai from Deny to Allow.
Firefox
  1. Click the crossed-out microphone icon in the address bar, clear the blocked permission and reload the page.
  2. To see every site's setting, open Settings > Privacy & Security > Permissions > Microphone.
iPhone and iPad
  1. In Safari, tap the page menu button in the address bar, choose Website Settings and set Microphone to Allow.
  2. If Safari never asks, open Settings > Safari > Microphone (Settings > Apps > Safari on iOS 18) and choose Ask or Allow.
  3. For Chrome on iPhone, open Settings > Chrome and turn on Microphone.
Android
  1. In Chrome, tap the icon to the left of the address, choose Permissions and turn on Microphone.
  2. If the switch is missing, open Settings > Apps > Chrome > Permissions and allow Microphone.
Windows
  1. Open Settings > Privacy & security > Microphone. Turn on Microphone access, Let apps access your microphone and Let desktop apps access your microphone. Browsers count as desktop apps.
  2. Open Settings > System > Sound. Under Input, choose your mic and check that its volume isn't at zero.
  3. Close apps that may be holding the mic, such as Zoom, Teams or Discord, then reload this page.
macOS
  1. Open System Settings > Privacy & Security > Microphone and turn on your browser. Quit and reopen the browser after you change it.
  2. Open System Settings > Sound > Input. Choose your mic and raise the input volume if the meter barely moves.

Already recorded it on a bad mic?

A mic test helps the next take. If the interview is already recorded on a laptop mic, in a noisy room or with the gain too high, Diffio restores the speech in that file: it removes background noise, reduces room echo and repairs some clipping. You hear the original and the restored speech side by side, so you can check the result before you use it.

The Free plan includes 3 uploads, audio or video, with a 2-minute preview of each result.

Mic test questions

How do I test my mic?

Press Start mic test and allow the microphone when your browser asks. The meter moves as you talk. Then press Record a test, stay quiet for 2 seconds, say a few sentences in your normal voice and listen back. The results under the player say whether the level, background noise, hum and tone are right, and what to change if they aren't.

Is this mic test free?

Yes. It runs in your browser, with no account and nothing to install.

Is my recording uploaded anywhere?

No. The recording and every measurement stay in this browser tab, and they're gone when you close it. The audio leaves your browser only if you choose to upload it to Diffio, which needs an account.

Why can't my browser find my microphone?

Usually the site or the browser isn't allowed to use it. Allow the microphone from the icon next to the address, then check your system's privacy settings: on Windows, Settings > Privacy & security > Microphone; on a Mac, System Settings > Privacy & Security > Microphone. Another app, such as Zoom or Teams, may also be holding the mic. There are steps for each browser and system on this page.

What is a good mic level?

Speech that peaks between about -12 and -6 dBFS, with the loudest moments staying under -3 dBFS. Much quieter than -24 dBFS and the voice sinks into the noise when you turn it up later. At 0 dBFS the waveform clips, which sounds harsh and can't be turned back down.

Why does my microphone sound muffled?

Something sits between the mic and your mouth (a laptop lid, a shirt over a lavalier, a hand), the mic points away from you, or a Bluetooth headset has switched to its narrow call mode, which cuts off everything above about 4 kHz. If a recording already sounds muffled, see how to fix bad mic audio.

Why does my mic hum or buzz?

A steady low hum at 60 Hz in the U.S. (50 Hz in much of the world) is electrical. It usually comes from a ground loop between a charging laptop and an audio interface, an unshielded cable lying across a power cord, or a guitar amp or light dimmer on the same circuit. Unplug the charger, separate the cables or try another USB port. For hum that's already in a recording, see how to remove hum, hiss and static.

Does the mic test work on iPhone and Android?

Yes, in Safari on iPhone and iPad and in Chrome on Android. Tap Start mic test, allow the microphone and hold the phone about 8 inches (20 cm) from your mouth with the bottom edge toward you, since that's where the main mic is.

Does this test change how my mic sounds?

No. It turns off the browser's noise suppression, echo cancellation and automatic gain, so you hear what the mic itself picks up. Video call apps turn those back on, so a call can sound a little different from this test.

Can Diffio fix a recording made on a bad mic?

Often. Diffio restores the speech in recordings you've already made: it removes background noise, reduces room echo and repairs some clipping. It works after the fact, not on a live mic or call. Results depend on the recording, so the Free plan gives you 3 uploads with a 2-minute preview of each result.