Decibel Shield — new data & tools

Measure the noise while it is happening, for as long as it lasts, and save a dated report with the session length and the quietest, average and loudest levels.

Combine sound levels the way they actually combine (two 60 dB sources make 63 dB, not 120), subtract a background reading with the 3 dB validity rule the standards use, energy-average readings, and convert decibels into ratios, pascals and watts.

The headphone test plays a tone to one channel at a time and asks which side you heard it from, so swapped left and right channels are a finding rather than a silence, alongside a dead side and a mono downmix.

The frequency content of whatever your microphone hears, 20 Hz to 20 kHz in logarithmic bands, with the loudest frequency named as you go and an optional peak hold for short events.

Our meter has had pages in Japanese, German, Spanish, Portuguese, French, Italian, Polish, Dutch, Korean and Indonesian since August.

Press Start, speak, and the page says whether your microphone works, which input the browser is using and how loud you are in decibels, with a live waveform.

Enter a decibel level and a distance and see the level anywhere else, or the distance at which it falls to a level you choose, using the free-field inverse-square law with its assumptions stated.

The same calibrated microphone pipeline as the decibel meter, shown as a traffic light the whole room can read: green under a quiet threshold you set, amber as it rises, red above a loud one, with a big display for the projector and a tally of seconds spe…

A reader pointed out that our England city pages said an area could be "#1 of 65" and "right at the England median" in the same sentence.

Twenty-one more cities, bringing the set to 29 across 23 states: what the quiet hours actually are, whether a real decibel limit exists, the code quoted verbatim, and where a complaint actually goes.

The first non-English page on the site: the browser decibel meter with Japanese explanatory copy, including the accuracy limits and a plain statement that the readings are not valid for Japanese workplace or noise-regulation compliance, which require a ce…

A sine-tone generator that runs in the browser, with left-only and right-only channel routing and twelve labelled frequency presets.

A list of the news coverage that has used our city noise data, with links to each story, plus what a journalist needs to use the datasets: 685 cities across the US, UK and Europe, all CC BY 4.0, with CSV and JSON downloads and a ready-made citation on eve…

Rendered Lden contour maps for 68 of the 74 mapped UK urban areas, composited from the official Defra and Welsh Government noise-mapping services.

Population noise-exposure figures for every UK urban area required to be mapped under the environmental noise regulations, taken from Defra for England and from the devolved administrations for Scotland, Wales and Northern Ireland.