Repetitive Sound in Game - A warning or notification?

[tinkertailor15]

Hello All,

Continuing my string of new player questions, here is one that is really puzzling me.

After I play for a time a sound will start repeating regularly through my speakers. It sound like cymbal but not a loud crash, more like when a cymbal is brushed. It will repeat 6 or 7 times then stop, returning after a while. I've searched a bit but cannot identify what's causing it.

As usual, readers, thanks for your helpful input.

Best Regards.