Mysterious sounds play when minecraft is not running

Minecraft is not running- the launcher is running.

The sound a slime makes when it lands and the pressure plate on/off sounds play on my computer when the minecraft application is off. The rain sounds also play on occasion.

Unknown how to reproduce- the sounds are very quiet and can be heard over the headphones or with the volume on high. One of my worlds has a redstone build involving a slime and a pressure plate, but that world is not running.