Voice Recorder

Browsers can clean up a microphone signal before it is recorded. The Voice setting turns on three of those filters: noise suppression (fans, traffic, keyboard), echo cancellation (sound from your speakers coming back into the mic) and automatic gain (keeps your level even when you lean back). It also asks for a mono recording, which is what a single voice needs.

Music / raw turns all three off and asks for stereo where the microphone has it. Noise suppression treats a held note or a quiet guitar decay like background noise and can cut it off. Automatic gain makes loud and soft passages sound the same. For anything musical, raw is the honest recording.

We recorded the same take in each format and measured the size per minute:

• As recorded (WebM with Opus in Chrome, Edge and Firefox; WebM or M4A in Safari, depending on the version): about 0.9 MB per minute. Opus is very good for speech at this size. It plays in browsers, VLC, Android and most chat apps, but some older Windows players and car stereos don't open it.
• MP3 at 192 kbps: about 1.4 MB per minute. It plays on everything, which makes it the safe choice for sending to someone else or uploading to a form.
• WAV: about 5.8 MB per minute for a mono Voice recording, about 11.5 MB for stereo. It is uncompressed 16-bit audio, the right input for an audio editor, a transcription service that asks for WAV, or archiving.

Converting doesn't improve quality. MP3 and WAV are made from the recorded Opus audio, so pick WAV for compatibility with editors, not for extra detail.

The meter shows how loud the microphone signal is, from silence on the left to the loudest the file can hold on the right. Green is a comfortable speaking level. Short yellow peaks are fine. If the last red bars light up and the warning about clipping appears, the sound is distorting: move back a little or turn down the input level in your system's sound settings. A meter that hardly moves usually means the wrong microphone is selected or a headset mic is muted with its own switch.

For speech, about a hand's width from a headset mic or 20 to 30 cm from a laptop or desk mic works well. Turning your head away from the microphone changes the level more than you'd expect.

1. Blocked permission. Click the lock or microphone icon in the address bar and allow the microphone for this site. On iPhone, check Settings, Safari, Microphone.
2. System privacy settings. On a Mac, System Settings, Privacy & Security, Microphone must include your browser. On Windows, Settings, Privacy, Microphone must allow desktop apps.
3. Another app has it. Video call apps sometimes hold the microphone. Quit the call and try again.
4. Bluetooth headsets sound muffled. Many headsets switch to a low quality call mode when their microphone is used. For better sound, use the laptop's own mic or a wired one.

The recording is kept in the tab's memory until you download it, at under 1 MB per minute, so even a two hour lecture fits easily. Don't close or reload the tab before downloading; the page asks for confirmation if you try while recording. On phones, locking the screen or switching to another app can pause or end the recording depending on the browser, so keep the page in front. For editing out a cough or a long pause afterwards, use a dedicated audio editor; this tool records and converts but doesn't cut.