Test the rpm accuracy of your turntable, whether 16, 33, 45, or 78.
RPM uses the gyroscope in your iPhone to determine the rotation speed of your turntable, automatically determines which speed setting you’re on and reports how accurate it is.
Simply place your iPhone on your turntable, close to the centre but doesn’t have to be over the centre spindle. As the iPhone rotates the display will remain stationary from your perspective for easy reading.
NEW Feature available to show a scrolling graph of the rpm accuracy variation over time, this shows wow/flutter effects, especially those associated with the turntable not being level. You can even detect the small drag caused by the stylus resting in the grooves of the record.
The graphs kicks in when the accuracy is below 1% and scales up to show extra detail if the turntable accuracy is below 0.5%.
The iPhone gyroscope is very accurate, however if you are in any doubt you should calibrate RPM first using a quality turntable of known rpm.
Major new feature available to show a scrolling graph of the rpm accuracy variation over time, this shows wow/flutter effects, especially those associated with the turntable not being level. You can even detect the drag caused by the stylus resting in the record grooves.
The graphs kicks in when the accuracy is below 1% and scales up to show extra detail if the turntable accuracy is below 0.5%
The display circle now turns solid green when the accuracy is below +/-1% as a quick indicator that all is good.
Link: here