The WOW measurement according to DIN IEC 386 is quite accurate in measuring relatively slow speed fluctuations in a range of <10Hz (WOW). Faster variations (flutter) are a problem to measure with a phone because audio can be sampled at a maximum rate of 44.1kHz which is limiting the measurement of fast fluctuations. Please put the device on a solid base for measurement in order to avoid shaking it which causes some minimal doppler effects and decreases the accuracy.
You can achieve better results by using our PC software Adjust+ (see www.adjust-plus.com)
Posted in: Common