Audio measurement uses the device microphone to track the rotational motion by measuring speed variations as frequency modulation of a 3150 Hz frequency from playing a test record. Digital signal processing then calculates RPM and provides wow and flutter results within the full range of 0.1 to 200 Hz. A classic method optimized for high accuracy without manual calibration.

Simply play test record, place microphone close to loudspeaker or headset to avoid excessive sound level. Sound level green: Ready to measure.

During measurement, sound level and RPM variation is shown. When measurement duration completes, the calculated RPM, wow and flutter is shown with the verified accuracy.

Wow and flutter is calculated as unweighted values representing the raw frequency modulation and weighted values representing perceived sound instability.

Weighting complies to the shared frequency curve of DIN 45507 and IEC 60386, with results reported as true RMS values.