RPM Speed & Wow

Andrea Martignano

About this app

RPM Speed & Wow 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!

Update history:
1.6.8
- Wrong message when the speed is "perfect": corrected.

1.6.7
- The offset correction now applies also to the text rotation.
- Big bug in offset-correction corrected.

1.6.5
- Correction for gyroscope sensor offset added: 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.

1.6.0
- Colorfest! Now the app becomes red where the turntable runs faster than the average, and blue where the turntable runs slower. You can see where the speed changes happen. Achtung: don't worry, variations are totally normal in every turntable!
- Sensor noise filtering algorithm was rewritten.
- Clearer (and greener) average line in the graph.

1.5.2
- Average line in the graph view added.
- Solved a graphic problem with certain text size general settings.

1.5.0
- Major update! Graph visualization of the acquired data.
- Better management of the sensor noise.
- Increased resolution of the acquired data.

1.1.2
- Wow algorithm's resolution improved.
- Minor graphic modifications.

1.1.1
- Wow calculation error message corrected.
- Calculation of the deviation from the correct speed corrected.

1.1
- Added Wow estimation!
- Added 16 2/3 rpm to the recognized speeds.
- Now the average RPM shows with 2 decimals.

1.0.1
- Minor update: controls if your smartphone has a gyroscope.

1.0
- First release.

Ratings and reviews

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.

This might be the most helpful app I've ever downloaded. It literally solved in 30 seconds a slight turntable speed calibration issue that I've been unable to solve by ear for 10 years. It's highly accurate and super easy. To get my phone in the center of the spinning record, I loaded an old 12" vinyl and put my 45 adapter on top of that, which created a flat surface at the center for my phone to sit on. Result? PERFECT pitch. I wish I'd found this app 10 years ago.

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!

What's new

Update to last Android API request and hopefully solved crashing problems