dB Scout: Honest Sound Meter

Most phone sound meter apps have two dirty secrets. dB Scout was built around fixing both.

Secret #1: a phone sound meter is only as honest as its reference point and its signal path. Two things go wrong in most apps. They record through Android's processed audio path, where automatic gain control quietly turns the level down as the room gets louder, so the reading stops climbing long before the noise does. And they never tell you where the top of their scale actually is. dB Scout does both differently. It meters raw, unprocessed PCM straight off the microphone with no auto-gain in the path, so a 20 dB rise in the room is a 20 dB rise on screen. And it shows you its own ceiling: a clear OVER RANGE warning plus a "Max readable here" readout, which moves up as you calibrate. You always know whether you are looking at a measurement or at the edge of the scale.

Secret #2: the ad ambush. The most-installed meter apps interrupt you with unclosable full-screen ads in the middle of a measurement. dB Scout never does. While you measure, there is only a small banner. A capped, occasional full-screen ad can appear between sessions, never during one. And a single $2.99 purchase removes all ads forever. No subscription. Nothing else to buy.

THE METER
• Big, readable number first: current level in huge fixed-width digits with AVG and MAX beside it
• Color-coded zone arc with a live needle, plus a rolling 60-second level strip
• dB(A), dB(C) and dB(Z) frequency weighting
• Fast / Medium / Slow / Slowest time weighting (IEC 61672-style response)
• Session min / max / average and Leq (equivalent continuous level)
• Held PEAK readout with one-tap re-baseline
• Frequency view: the low / mid / high split of what the mic is hearing, and which band dominates

HEARING SAFETY: FREE FOR EVERYONE
• Tracks how long each session spends at or above 85 dB, the NIOSH reference level for hearing risk
• Clear warnings when exposure adds up
• Not locked behind any purchase

SESSION HISTORY
• Every measurement session is saved automatically: duration, min/max/avg, Leq, time over 85 dB and a level profile
• Browse past sessions, inspect the detail view, export any session as CSV, delete what you don't need

CSV EXPORT
• Share real CSV files with readable filenames, into email, Drive, Sheets, anywhere
• Per-reading live-session export and per-session history export

CALIBRATION: THIS IS WHAT MAKES THE NUMBERS REAL
• Guided wizard: measure a known reference (an acoustic calibrator, a sound level meter you trust, any level you know) and dB Scout computes your offset
• The offset shifts the entire scale, ceiling included. Calibrate against a 94 dB reference and a 114 dB source reads 114, not a pinned maximum
• Wide offset range, sanity checks that catch implausible measurements (like calibrating against silence), and one tap resets to zero

HONEST BY DESIGN
• dB Scout measures your phone's built-in microphone. It cannot select an external or USB microphone as its input, so it does not claim to
• Absolute accuracy depends on your phone's microphone and on your calibration. Uncalibrated, treat the numbers as relative; calibrated against a known reference, they are as good as that reference
• Great for relative measurements, trends, noise checks, apartment evaluations, workplace awareness
• For legally binding measurements, use a certified Class 1/2 instrument. No phone app is one, whatever it claims

PRIVACY
• Audio is processed in real time only, never recorded, never stored, never transmitted
• No account. Works completely offline.
• Privacy policy: https://griswoldlabs.com/privacy/sound-meter/

One-time $2.99 Pro removes ads forever. Everything else (hearing safety, history, export, calibration) is free for everyone.

Recent changes:
1.2.17: the ad banner now fits the screen in landscape — no longer runs under the side navigation bar or stays cropped after turning the phone upright.