Voice Recorder
Record audio from your microphone and download it, entirely in your browser — nothing is uploaded and no account is needed.
Rounding error is only noise when the recording is loud
Recording means rounding every sample to the nearest value the format can hold. The difference between what arrived and what got stored is usually called noise, and for a loud signal that is fair: the rounding lands somewhere arbitrary each time and the error has no pattern.
For a quiet signal it is not. A quiet wave crosses only a handful of levels, so it gets rounded the same way every cycle and the error repeats along with it. Measuring where that error energy actually sits — on harmonics of the note, or spread across the spectrum:
| Signal level | Error on harmonics | With dither |
|---|---|---|
| 90.0% of full scale | 0.4% | 1.1% |
| 10.0% of full scale | 10.3% | 1.1% |
| 2.0% of full scale | 74.7% | 1.5% |
| 0.5% of full scale | 83.4% | 1.5% |
At full scale the error is scattered everywhere and behaves like hiss. At half a percent of full scale, 83% of it is stacked on harmonics of the note being recorded — which is distortion, not noise. It follows the voice, changes pitch with it, and sounds like a fault rather than a background.
So the fix is to add noise on purpose
Dither is a small amount of random noise added deliberately, before the rounding. It makes each rounding decision independent of the last, which breaks the pattern — the third column above. The structure disappears completely at every level, and at the quietest one the harmonic share drops by a factor of 57.
The price is real, and worth stating plainly: dither roughly doubles the total error power, and unlike the undithered case it stays flat however quiet the signal gets. You are trading a smaller, uglier error for a larger, duller one. A quiet passage recorded with dither has a faint constant hiss; the same passage without it has a buzz that tracks the melody. Every professional converter dithers, and this is why.
More resolution does not remove the problem, it relocates it. A signal at 2% of full scale behaves like a loud one at 16 bits, because 2% of full scale is still hundreds of levels up. Go quiet enough and the structure comes back at any bit depth.
And the familiar rule holds, once there are enough bits
The textbook figure for signal-to-noise ratio is 6.02n + 1.76 decibels for n bits. Measured against a full-scale sine rather than quoted:
| Bit depth | Measured | Predicted | Short by |
|---|---|---|---|
| 4 bits | 23.3 dB | 25.8 dB | 2.6 dB |
| 6 bits | 36.5 dB | 37.9 dB | 1.4 dB |
| 8 bits | 49.3 dB | 49.9 dB | 0.6 dB |
| 12 bits | 73.9 dB | 74.0 dB | 0.1 dB |
| 16 bits | 97.8 dB | 98.1 dB | 0.3 dB |
The formula assumes the error is spread evenly — the same assumption that fails for quiet signals. So it is least accurate exactly where the coarsest quantisers live, over- promising by 2.6 dB at 4 bits and settling to within a tenth of a decibel by 12. Sixteen bits reaches the 98 dB that made compact discs sound the way they did.
How to use
- Allow microphone access.
- Record, then play back to check the level.
- Download the file before leaving the page.
- Get close to the microphone and reduce room noise.
Frequently asked questions
Does my recording get uploaded?
No. Everything happens in your browser and the audio never leaves your device, which matters for interviews, notes and anything confidential. It also means the recording exists only in the page until you download it.
Will I lose the recording if I navigate away?
Yes. The audio is held in the page, so closing the tab or reloading discards it. Downloading before doing anything else is the habit worth having, and it is the most common way people lose a recording here.
How do I get better sound quality?
Get closer to the microphone, which improves the ratio of your voice to the room by more than any setting will. Reduce hard reflective surfaces, turn off fans and air conditioning, and avoid recording in a large empty room. Proximity and a quiet space beat equipment.
Why does my recording sound thin or distant?
Almost always distance from the microphone. Laptop microphones sit far from your mouth and pick up the whole room, so the voice arrives with a great deal of reflection. Any external microphone placed close to the speaker is a substantial improvement.
Can I record a phone call or another app's audio?
Not through this. Browsers only grant access to microphone input, not to system audio, deliberately. Capturing other applications requires dedicated software, and recording calls has legal requirements that vary considerably by jurisdiction.
What format is the file?
Whatever the browser's recorder produces, commonly a WebM or Ogg container with an Opus stream — efficient and widely supported, though some older editing software will not open it directly. Converting afterwards is straightforward if you need a WAV or MP3.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.