All Tools
Exhaust dB Meter
Phone-mic sound meter with peak hold and an indicative pass/fail against the ~90 dB(A) reference used for modified exhaust enforcement — and the measurement procedure that matches how it is actually tested.
Estimated level
-10 dB
Peak hold
— dB
raw -100.0 dBFS
406080100120 dB
Indicative verdict (peak vs ~90 dB(A) reference)
Peak measured ~-10 dB — under the commonly cited ~90 dB reference
Indicative only — a phone mic is not a calibrated meter. Calibrate against a known source for closer numbers, and never argue a roadside case with an app reading.
How enforcement measures (and how to measure like them)
- • Hold the phone ~0.5 m from the tailpipe, at 45° to the outlet — never directly in the blast.
- • Puspakom revs the engine to a set point (typically around three-quarter of the redline); JPJ roadside checks use their own procedure. Both focus on the peak — watch Peak Hold, not the live number.
- • The commonly cited official reference for modified exhausts is ~90 dB(A); the legal noise standard (MS 1525 / draft vehicle-noise MS) and the exact JPJ procedure carry the real weight.
- • Bikes are enforced harder: JPJ has taken modified-exhaust riders to court, not just summons.
Calibrate in 30 seconds
- • Quiet room: should read ~30–40 dB. Busy traffic: ~75–85 dB. If your numbers are far off, adjust the calibration value (default 90).
- • Best: stand beside someone with a real sound-level meter (or a workshop dB tester) and match the reading — then your phone is good to ±2–3 dB in this range.
- • iOS mics typically need a lower calibration number than Android mics; the offset is per-device, so recalibrate when you switch phones.
Good to know
- A phone is not a calibrated sound meter. The result is indicative (± a few dB); calibrate the offset against a known source for closer numbers.
- Enforcement focuses on the PEAK at a set engine speed — watch Peak Hold, held ~0.5 m from the tailpipe at 45°.
- The commonly cited reference for modified car exhausts is ~90 dB(A); the exact legal standard and JPJ roadside procedure always take precedence.
- JPJ has moved from summonses to court action for extreme exhaust modifications — measure before you get measured.