Comparative study of the performance of smartphone-based sound level meter Apps

David P. Robinson , James Tingay

New Zealand Acoustics, 28(2), pp.4- 11 . (2015).

An increasing prevalence of sound level meter Apps may appear to be a concern to manufacturers of metering equipment but such systems are readily disregarded by professionals due to unacceptable inaccuracy, incorrect measurement methods or parameters. On a technical basis, the (typically MEMS) microphone specifications are the primary limitation to the capabilities of such devices in meeting the requirements. This considered, the attachment of a high-quality condenser microphone and pre-amplifier, as used on professional equipment, may appear to be a solution for low-cost metering that meets IEC-61672, but it is shown that many other equipment factors affect the performance of the system, and conformance to the specifications. This study investigates the premise that, while it may be argued that approximate readings, provided by smartphone metering, can at least offer an indication that further investigation may be necessary, there exists the real chance that the shortfalls in equipment properly measuring the full range of required acoustical parameters will lead to non-detection of significant workplace or environmental noise problems.