It interference from another cable. try moving the cables about to see which one it is.
I used to get it from an old mouse. When it was moved it would make trumping noises in the speakers. Re-route the cables and its gone...
This thread is now locked and can not be replied to.
What is Amazon Go and will it come to the UK? The store without checkouts or queues
1995-2015: How technology has changed the world in 20 years
Hands-on with the Star Wars fighting drones you can fly yourself
15 macOS Sierra tips | How to use macOS Sierra: Secret tricks and best new features in Apple's new…