ClockSpeed 4+

Overview ClockSpeed
The App ClockSpeed records the ticking of your watch or clock, and analyses the sound to find the precision and accuracy of it.
Note: You need to know the clock you are measuring, you need to know how it is designed and how fast it is built to run. The App compares the reality with what you choose in the settings - the result is the difference between the reality and the intended theory. The App knows only how fast the clock ticks, not how fast it should tick - you need to select this setting for an accurate result.
 
The sound is recorded lossless with a sampling rate of 192kHz, which gives it a precision of about a ½ second deviation per day, with a recording of just about 1 minute.
You can import the sound recorded with another tool, e.g. the Apple Voice Memos App, which can record maximal with 48kHz, which reduces the accuracy of the App result to a deviation of about 2s per day.
 
The App works with some assumptions:
1) The loudest noise on your recording needs to be the ticking. Side noises are OK as long they are quieter. Passing cars or chirping birds can be very loud, so do not expect a good result with a poor recording. Some single short noise peak can be filtered out by the App.
2) Listen to your recording – can you hear the ticking? If not, the result might be inaccurate. Watch the provided picture of the sound, you usually can see side noises and disturbances.
3) You know how fast the clock should be, and how many ticks are expected per second. Imagine a pendulum clock, which ticks once per second, and your wrist watch ticks maybe 8 times a second. You need to select the correct speed in settings, a wrong choice leads to a wrong result.
4) Each tick sounds identical, but in reality, they are not identical, therefore the measure is not perfect, but still very good. Do not try to verify the App with a ticking quartz clock, because that type of clocks has big differences in the single ticks. The balance wheel of a mechanical watch creates much more constant noises as a quartz clock with its plastic gears. Anyway, expect small variations of the result with different recordings, even if you do them just one after the other.