Acoustic measurement on a smartphone depends on its microphone, operating-system audio processing and hardware. Calibration adjusts overall sensitivity, but does not turn a phone into a standards-compliant sound level meter.
1. Understanding calibration
A sensitivity mismatch causes an offset in the displayed levels, expressed in decibels. The app lets you adjust this offset against a reference. However, the microphone's frequency response, saturation, any audio processing and self-noise remain sources of error.
2. Comparison with a reference instrument
- Use a sufficiently stable sound source and a suitable reference sound level meter.
- Position the smartphone and the reference microphone close together without acoustically obstructing one another.
- Select comparable indicators (for example, LAF or LAeq over the same measurement period).
- Adjust microphone sensitivity in Sound Analyzer App's calibration menu to bring the readings closer together.
- Check the accuracy of the adjustment by comparison, if possible using different signals at several sound levels.
3. Practical precautions
- Avoid direct wind and sounds that could overload the microphone.
- Keep a repeatable geometry away from nearby obstructions.
- Recheck calibration if you change devices.
4. What accuracy can be expected?
No universal accuracy specification applies to Android smartphones. Unless a particular device has been characterized, the results should be treated as indicative. Use suitable compliant instruments for regulatory measurements.