Articles and sound guides

The practical difference between dB and dBA, what A-weighting does, why dBA is widely used, and when another metric may be needed.

Why a 3 dB increase doubles sound energy but not perceived loudness, what a 10 dB change means, and how the NIOSH 3 dB exchange rate works.

A clear explanation of what decibels measure, why the dB scale is logarithmic, how dB differs from dBA, and how to interpret common level changes.

An explanation of sound pressure, SPL, the 20 micropascal reference, the SPL formula, distance effects, and the limits of smartphone measurements.

Why sound levels use a logarithmic scale, what common dB changes mean physically, and why decibel values cannot be handled like ordinary linear numbers.

How the NIOSH 85 dBA model calculates occupational exposure time from 85 to 115 dBA, and why the result is not a personal safety guarantee.

Compare NIOSH and OSHA noise limits, including criterion levels, exchange rates, dose, TWA, hearing conservation, and legal status.

Why no single decibel level is safe in every situation, how sound level and duration interact, and how NIOSH, OSHA, WHO, and EU guidance differ.

What noise dose percentages mean, how sound level and exposure time accumulate, what 100% dose represents, and why NIOSH and OSHA dose values differ.

Why 85 dBA appears in hearing-risk guidance, what NIOSH means by 85 dBA for eight hours, and why it is not a universal safety threshold.

How accurate smartphone decibel meter apps can be, why Android results vary, what calibration can improve, and when a professional meter is required.

How to align a smartphone sound meter app with a reliable reference, calculate an offset, verify several levels, and understand what calibration cannot fix.

Measure environmental sound with an Android phone while controlling position, distance, duration, settings, and common sources of error.

Compare phone sound meter apps with professional meters for accuracy, calibration, peak capture, compliance, cost, and practical use.

Why sound meter apps can display different dB values because of weighting, response time, averaging, calibration, audio processing, and phone hardware.

Typical baby crying decibel levels at caregiving distance, why close-range readings can be much higher, and what a phone measurement can and cannot show.

Typical concert decibel levels, how audience position changes the reading, and why LAeq, maximum, peak, and exposure duration must be kept separate.

Typical lawn mower decibel levels at the operator position, why mower noise changes under load, and when hearing protection may be appropriate.

Typical decibel levels for normal conversation, why speech readings vary with distance and vocal effort, and how to measure conversation sound with a phone.

Typical vacuum cleaner decibel levels, why readings change with the model, floor, room, and distance, and how to make a repeatable phone comparison.