1. I recommend fiddling with the settings some while timing a baseline watch (that you've already timed using some other method) so that you know you're getting an accurate reading.I own a clock repair shop and i got this app because i figured it would be something good to use on house calls.
2. Also, there seems to be very little documentation on what the app is reporting on my phone's screen.I've been using this for a couple of years now, on different Android versions.
3. The downside to this device is that you need to be able to fit your phone inside the clocks being tested.
4. Clip-on timegrapher microphones solve the lack of sensitivity, and running it through a beat indicator pick-up ($40-$50) on Timesavers Website.
5. I don't know if it is that the watches are worn or the app not working on the higher frequencies with the remote phone mike.
6. But: this app is the best current one out there-This app had been useful for regulating my mechanical watches, although it's not terribly accurate.
7. Detects beats per hour with phone microphone set against watch case, which is all you really need.
8. Using this app and the built-in mic on my Galaxy S8+, I was able to very easily regulate my 1980s Vostok Amphibia from -500s/d to -4s/d.
9. It only gives you a 30 minute free trial, but it's well worth the $5 to upgrade and keep using it.
10. Looked good at first but after paying $4.99 for the full version and using it a while, I noticed that everything is either dead on or +/- 7, 15, 21,28, 35 etc.
11. Tried several watches from 18-28.8kbph and with the exception of 15, the error rate was always in multiples of 7.