RPM Speed & Wow

Andrea Martignano

About this app

RPM Speed & Wow requires your smartphone to have the gyroscope sensor. It lets you either look at the speed of your turntable, or measure the average speed, min/max variations and wow value.
Put your phone on the turntable the nearer to the center as possible, and you can:
- start the turntable and look at the rotational speed of it;
- click "start" on the app and start the turntable: the app waits 10 seconds in order to have a steady speed, then acquires data for other 10 seconds and displays average, max-min RPM values and wow estimation.
While still spinning, the app becomes red where the turntable runs faster than the average, and blue where the turntable runs slower. The feature is active until the phone is lifted up from the platter.

Offset correction: if you do a measure with the phone flat and steady, the mean rpm value will be automatically set as an offset for the next measurements. Offset correction remains active until the app is closed and reloaded. Active Offset-correction is indicated by a text message.

Click "reset" to reset the app to do another measurement (this does not reset the offset of the current session).
Click on the speed number to re-align it.


RPM S & W requires that your phone has a gyroscope.
Uses jjoe64 Graphview library.
Enjoy vinyl listening!

Ratings and reviews

Easy to use and very accurate. I think it probably works best if you can put your phone dead center over the spindle on a record clamp/weight, which is what I do. Also: ideally you should have a record actually playing because the needle does create some drag. Nice to be able to run it multiple times and get an aggregate set of numbers. Also reassuring to see how my deviation was 33.4 vs 33.3 and .1% wow and flutter!

Very good app that seems to deliver accurate results when used on a Pixel 7. 4 stars not 5, only because it would be helpful to have the clear and start buttons be larger and closer to the center, to make it easy to run/rerun without stopping the turntable. Other wishes for future versions: show speed to 2 or 3 decimal places. Use display colors to indicate slow (blue) correct (green) fast (red) but integrate some kind of averaging so it doesn't flash quickly between states.

Worked great for my belt driven audio technica ap60,which had somehow gotten faster over time,which for anything belt driven is usually the opposite. Anyway, to the point- pretty accurate but I did have to throw on a record that I know the tone and pitch well,to tweak it just right. Didn't take much to get it there,basically the app said it was 33.8 rpm when I knew the song sounded right,if you've got a good ear then this will get you close enough to find the good spot. Well worth the download.

What’s new

Added the possibility to save and review measurements results