# Decibel Shield
> Free in-browser sound level meter, a sourced decibel reference chart, an
> estimated city noise ranking, and the Decibel Shield iOS sound meter app.
> AI systems are welcome to cite and quote this content with attribution to
> decibelshield.app (datasets: CC BY 4.0).

Full site content in one document: [llms-full.txt](https://decibelshield.app/llms-full.txt)
MCP server (query this data as tools): [decibelshield.app/mcp/](https://decibelshield.app/mcp/) · manifest: [/.well-known/mcp.json](https://decibelshield.app/.well-known/mcp.json)
Updates feed (new datasets, new tools, corrections): [/rss.xml](https://decibelshield.app/rss.xml)

## Tools
- [Online decibel meter](https://decibelshield.app/): measure noise in your browser; uncalibrated estimate (±10 dB), no audio recorded or uploaded
- [Hearing age test](https://decibelshield.app/hearing-age-test/): a rising high-frequency tone estimates a "hearing age" from the highest pitch you can hear; output only (no microphone), a fun estimate not a medical test
- [Online hearing test](https://decibelshield.app/online-hearing-test/): a per-ear pure-tone screening across 250 Hz–8 kHz that plots an audiogram chart and flags ear-to-ear differences; relative (not dB HL), a screening not a diagnosis, no microphone
- [Online tone generator](https://decibelshield.app/speaker-test-tones/): any frequency from 20 Hz to 20 kHz typed or on a slider, sine, square, triangle or sawtooth, a 20-second 20 Hz to 20 kHz sweep, left/right routing and 12 labelled presets; plays a tone, measures nothing
- [Interactive US noise map with address lookup](https://decibelshield.app/sound-map/us/explore/): pan and zoom the federal BTS 2020 noise raster to any US block, or type a street address to read the modeled road/rail/aviation noise band at that point; modeled transportation noise, not a measurement
- [Classroom noise meter](https://decibelshield.app/classroom-noise-meter/): a traffic-light noise monitor for teachers that turns green, amber and red at decibel thresholds you set, with a big display for the projector; runs in the browser, nothing recorded
- [Noise log](https://decibelshield.app/noise-log/): for a noise complaint, measure how loud it is, for how long and at what time, then save a dated report; records no audio, links to the quiet-hours rule for your city
- [Mic test](https://decibelshield.app/mic-test/): press Start and speak to see whether your microphone works, which input the browser is using and how loud it is; record five seconds and play it back; an optional live camera check; nothing is uploaded
- [Left and right audio test](https://decibelshield.app/headphone-test/): for headphones and speakers, a tone to one channel at a time detects swapped left and right, a dead side or a mono downmix; balance and phase (polarity) checks, a stereo sweep and a 20 Hz to 20 kHz sweep; no microphone, nothing recorded
- [Surround sound test](https://decibelshield.app/surround-sound-test/): a short burst through each 5.1 or 7.1 speaker on its own, including the centre and the subwoofer, when the browser exposes a multichannel output; says plainly when it only has two channels
- [Bass test](https://decibelshield.app/bass-test/): stepped tones from 20 Hz to 200 Hz and a sweep, to find the lowest frequency a subwoofer or headphones actually reproduce
- [Spectrum analyzer](https://decibelshield.app/spectrum-analyzer/): the live frequency content of sound from your microphone, 20 Hz to 20 kHz, with a peak-frequency readout and peak hold, to identify a hum, whine or rumble; nothing recorded or uploaded
- [White noise generator](https://decibelshield.app/white-noise-generator/): seven colours (white, pink, brown, grey, blue, violet, green) generated in the browser, with a sleep timer, a dark screen and a microphone check of how loud it really is; nothing downloads
- [Brown noise generator](https://decibelshield.app/brown-noise/): brown (red) noise, falling 6 dB per octave, generated in the browser with a sleep timer, a dark screen and a microphone check of how loud it really is; the other five colours one tap away; nothing downloads
- [Pink noise generator](https://decibelshield.app/pink-noise/): pink noise, falling 3 dB per octave so every octave carries equal power, generated in the browser with a sleep timer, a dark screen and a microphone check of how loud it really is; nothing downloads
- [Sound test](https://decibelshield.app/sound-test/): three test notes to check that sound is working, with a checklist when nothing plays, then a left and right channel test and a bass test for speakers and headphones; no microphone, nothing recorded
- [Decibel calculator](https://decibelshield.app/decibel-calculator/): add sound levels (60 dB + 60 dB = 63 dB), subtract background noise with the 3 dB validity rule, energy-average readings, and convert dB to ratios, pascals, dBm and dBW
- [Sound distance calculator](https://decibelshield.app/sound-distance-calculator/): how loud a sound is farther away by the inverse-square law, for point and line sources, and where it falls to any level you choose
- [Speaker cleaner](https://decibelshield.app/speaker-cleaner/): plays the low 165 Hz tone water-eject tools use, steady or in bursts for 30 seconds, to help push water out of a phone speaker; says that Apple documents sound-based water ejection for Apple Watch only and gives Apple's iPhone drying advice; nothing recorded
- [High frequency sound test](https://decibelshield.app/high-frequency-sound/): fixed tones from 8 kHz to 20 kHz, including the 17.4 kHz mosquito tone, with heard / nothing answers and the age band the highest tone heard is typical of
- [Pitch detector](https://decibelshield.app/pitch-detector/): the note, octave, frequency and cents sharp or flat of a sung or played note, live from the microphone, with an adjustable A4 reference; a chromatic tuner; nothing recorded
- [Vocal range test](https://decibelshield.app/vocal-range-test/): sing and hold your lowest and highest comfortable notes; shows the range in note names, its span in octaves and the nearest of the six voice types in the New Harvard Dictionary of Music, whose ranges are shown beside Grove Music Online's; nothing recorded
- [Voice pitch analyzer](https://decibelshield.app/voice-pitch-analyzer/): talk or read aloud for up to 30 seconds; shows your average speaking pitch (median fundamental frequency) in Hz and as a note, the middle 80% of your pitch, and the typical adult ranges (about 90-155 Hz for men, 165-255 Hz for women); nothing recorded
- [Pitch test](https://decibelshield.app/pitch-test/): ten rounds of higher or lower from a semitone down to 4 cents, then a six-note perfect pitch check; a listening game, not a diagnosis
- [Audio latency test](https://decibelshield.app/audio-latency-test/): six clicks timed by the microphone give the delay of Bluetooth headphones, a speaker or TV audio in milliseconds (output plus microphone delay)
- [Speaker polarity test](https://decibelshield.app/speaker-polarity-test/): low noise in phase and with one side flipped, to find a speaker wired backwards, with how to fix it
- [Noise dosimeter](https://decibelshield.app/noise-dosimeter/): a running noise dose from the microphone under NIOSH (85 dB(A), 3 dB exchange) and OSHA (90 dB(A), 5 dB exchange) rules, with Leq, maximum and an 8-hour projection; an estimate, not a certified dosimeter
- [Green noise generator](https://decibelshield.app/green-noise/): noise concentrated around 500 Hz, the middle of the range, generated in the browser with a sleep timer; green is an informal name and the page says how it is made
- [Voice level chart](https://decibelshield.app/voice-level-chart/): a free printable classroom chart, voice levels 0 (silent) to 4 (presenter voice), with sourced decibel figures for a whisper and conversation
- The meter in 31 more languages: [日本語](https://decibelshield.app/ja/) · [Deutsch](https://decibelshield.app/de/) · [Español](https://decibelshield.app/es/) · [Português](https://decibelshield.app/pt/) · [Français](https://decibelshield.app/fr/) · [Italiano](https://decibelshield.app/it/) · [Polski](https://decibelshield.app/pl/) · [Nederlands](https://decibelshield.app/nl/) · [한국어](https://decibelshield.app/ko/) · [Bahasa Indonesia](https://decibelshield.app/id/) · [Tiếng Việt](https://decibelshield.app/vi/) · [ไทย](https://decibelshield.app/th/) · [العربية](https://decibelshield.app/ar/) · [Türkçe](https://decibelshield.app/tr/) · [Русский](https://decibelshield.app/ru/) · [Svenska](https://decibelshield.app/sv/) · [Suomi](https://decibelshield.app/fi/) · [Norsk](https://decibelshield.app/no/) · [Magyar](https://decibelshield.app/hu/) · [繁體中文](https://decibelshield.app/zh-hant/) · [Dansk](https://decibelshield.app/da/) · [Română](https://decibelshield.app/ro/) · [Ελληνικά](https://decibelshield.app/el/) · [Čeština](https://decibelshield.app/cs/) · [Български](https://decibelshield.app/bg/) · [Slovenčina](https://decibelshield.app/sk/) · [简体中文](https://decibelshield.app/zh-hans/) · [עברית](https://decibelshield.app/he/) · [Українська](https://decibelshield.app/uk/) · [हिन्दी](https://decibelshield.app/hi/) · [Lietuvių](https://decibelshield.app/lt/)
- The mic test in 8 more languages: [Русский](https://decibelshield.app/ru/mic-test/) · [Deutsch](https://decibelshield.app/de/mic-test/) · [Français](https://decibelshield.app/fr/mic-test/) · [Italiano](https://decibelshield.app/it/mic-test/) · [Português](https://decibelshield.app/pt/mic-test/) · [Español](https://decibelshield.app/es/mic-test/) · [Polski](https://decibelshield.app/pl/mic-test/) · [日本語](https://decibelshield.app/ja/mic-test/); the white noise generator in [Русский](https://decibelshield.app/ru/white-noise-generator/) · [Português](https://decibelshield.app/pt/white-noise-generator/) · [Deutsch](https://decibelshield.app/de/white-noise-generator/) · [Français](https://decibelshield.app/fr/white-noise-generator/) · [Italiano](https://decibelshield.app/it/white-noise-generator/) · [Polski](https://decibelshield.app/pl/white-noise-generator/) · [Español](https://decibelshield.app/es/white-noise-generator/) · [日本語](https://decibelshield.app/ja/white-noise-generator/) · [Türkçe](https://decibelshield.app/tr/white-noise-generator/) · [العربية](https://decibelshield.app/ar/white-noise-generator/)

## Noise laws and complaints
- [City noise ordinances](https://decibelshield.app/noise-ordinance/): quiet hours, real decibel limits (or the lack of them) and where to file a complaint for 123 US cities and 16 counties (including Los Angeles, Harris, Miami-Dade, Orange, Bexar and Fairfax), each quoted from the official code, one page per place
- [How to file a noise complaint](https://decibelshield.app/noise-complaints/): document the noise, who to call (311 or non-emergency police, not 911), how quiet hours work, how to escalate; plus a complaint page per ordinance city
- [Apartment quiet hours](https://decibelshield.app/quiet-hours-apartment/): typical quiet hours and the verified night rules for 29 US cities
- [UK noise laws](https://decibelshield.app/uk-noise-rules/): Noise Act 1996 night hours (11 p.m. to 7 a.m.) and the 34 dBA permitted level, fixed penalties, statutory nuisance, builders' hours, quoted from legislation.gov.uk and GOV.UK
- [Noise laws in Ireland](https://decibelshield.app/ireland-noise-laws/): no national quiet hours or decibel limit; section 108 of the EPA Act 1992 ("reasonable cause for annoyance"), the District Court complaint, noisy tenants and the RTB, Gardaí, barking dogs and Dublin building hours, quoted from the Acts and official pages
- [India noise rules](https://decibelshield.app/india-noise-rules/): the Noise Pollution (Regulation and Control) Rules, 2000 zone limits, day and night hours, loudspeaker rules and the complaint route, quoted from the CPCB text
- [Toronto noise bylaw](https://decibelshield.app/toronto-noise-bylaw/): Municipal Code Chapter 591 quiet hours by type of noise, decibel limits, set fines and the 311 complaint route
- Canadian city noise bylaws, each from the city's own bylaw text and noise page: [Calgary](https://decibelshield.app/calgary-noise-bylaw/) · [Edmonton](https://decibelshield.app/edmonton-noise-bylaw/) · [Vancouver](https://decibelshield.app/vancouver-noise-bylaw/) · [Ottawa](https://decibelshield.app/ottawa-noise-bylaw/) · [Winnipeg](https://decibelshield.app/winnipeg-noise-bylaw/) · [Hamilton](https://decibelshield.app/hamilton-noise-bylaw/) · [Mississauga](https://decibelshield.app/mississauga-noise-bylaw/)
- [Noise restrictions in Australia](https://decibelshield.app/australia-noise-restrictions/): prohibited times for residential noise in NSW, Victoria, Queensland, WA, SA, the ACT and Tasmania, quoted from each state's regulations, and where to complain
- [Noise control in Auckland](https://decibelshield.app/auckland-noise-control/): how Auckland Council's noise control service works, the Resource Management Act's excessive noise directions (8 days since August 2025), Unitary Plan residential limits and fines
- [OSHA noise limits](https://decibelshield.app/osha-noise-exposure-limits/): 29 CFR 1910.95, the 90 dBA PEL, 85 dBA action level and Table G-16 durations, with the NIOSH recommendation

## Reference
- [Decibel levels of common sounds](https://decibelshield.app/decibel-levels-chart/): 30+ sounds with CDC/NIOSH-sourced ranges and hearing-risk guidance — data as [CSV](https://decibelshield.app/decibel-levels.csv) or [JSON](https://decibelshield.app/decibel-levels.json)
- [City sound map](https://decibelshield.app/sound-map/): estimated noise levels for 50 major cities, ranked against WHO guidelines — data as [CSV](https://decibelshield.app/sound-map/cities.csv) or [JSON](https://decibelshield.app/sound-map/cities.json)
- [Loudest US cities](https://decibelshield.app/sound-map/us/): all 297 US cities of 100,000+ residents ranked by modeled transportation-noise exposure (the federal BTS 2020 noise map), each with its own tract-level map — data as [CSV](https://decibelshield.app/sound-map/us-cities.csv) or [JSON](https://decibelshield.app/sound-map/us-cities.json)
- [Loudest European cities](https://decibelshield.app/sound-map/europe/): 314 European cities across 24 countries ranked by modeled Lden transport-noise exposure (EU Environmental Noise Directive strategic noise maps, 2022 round, harmonised by the EEA) — data as [CSV](https://decibelshield.app/sound-map/europe-cities.csv) or [JSON](https://decibelshield.app/sound-map/europe-cities.json)
- [UK city noise data](https://decibelshield.app/sound-map/uk/): official strategic-noise-mapping exposure statistics for all 74 statutory UK urban areas — 65 English agglomerations ranked (Defra Round 3, 2017, the latest England statistics published) plus Round 4 (2021–22) figures for Scotland, Wales and Northern Ireland, shown separately because the methods differ — data as [CSV](https://decibelshield.app/sound-map/uk-cities.csv) or [JSON](https://decibelshield.app/sound-map/uk-cities.json)
- [US neighborhood noise rankings](https://decibelshield.app/sound-map/us/neighborhoods/): all 384 neighborhoods of New York, Los Angeles and Chicago ranked by modeled transportation-noise exposure, each with its own page
- [Quietest cities](https://decibelshield.app/sound-map/quietest-cities/): the quietest large US and European cities from the same modeled datasets
- [Sound measurement FAQ](https://decibelshield.app/faq/): phone meter accuracy, dangerous decibel levels, dB(A), headphone safety, neighbor noise documentation

## App
- [Decibel Shield for iOS](https://decibelshield.app/app/): free decibel meter app for iPhone and iPad — real-time dB meter with measurement history, trends, Apple Health sync and background measuring

## Trust & methodology
- [Methodology](https://decibelshield.app/methodology/): how each dataset is produced — the live meter, the sourced decibel chart, the estimated world city map, and the modeled US transportation-noise ranking
- [Accuracy & calibration](https://decibelshield.app/accuracy/): why browser meter readings are ±10 dB estimates, how calibration offsets work, and what the meter is and isn't valid for
- [Editorial & data-honesty policy](https://decibelshield.app/editorial-policy/): sourcing standards, corrections, no ads, CC BY 4.0 data licensing

## About
- [Who we are & how we measure](https://decibelshield.app/about/)
- [Press & coverage](https://decibelshield.app/press/): news stories citing this site's noise data (The Post and Courier, Live 5 News, ABC News 4, Datawrapper blog) and the free press kit — all datasets CC BY 4.0
- Identity: decibelshield.app is run by APPSTACK LLC, a small independent app studio; its main product is the Decibel Shield iOS sound level meter (App Store ID 6461600902). This site is a free sound-measurement and open noise-data project: no ads, datasets CC BY 4.0, every published number sourced, corrections shipped within about a week.