I've been quite annoyed trying to use the timer because I can't seem to get it to play a sound, which is kinda the whole fricking reason for setting a timer.
I'm I missing something, or is the point of the timer feature to show you a silent negative countdown of how long ago you missed what you used the timer app to remind you about when you finally remember?
You. Had. One. Job.
The clock app timer notification tones can be set by selecting the timer tab, select the 3 vertical dots in the upper right hand corner and select settings. Select the sound entry under the timer label and select a tone or use the plus symbol to bring up sound picker and select a custom tone. If you have used system settings, apps, ciock, to modify the timer notifications I would recommend cleaning the clock app cache and data for a fresh clean start.