Beolab 5 strange sound...

Hey there and happy easter !

I've noticed that one of my Lab5's emits a strange sound from both high and mid tweeters when its on..

Its not hearable while music is playing its hard to describe what it sounds like ... It sounds like a tattoo machine but not that loud...

The speakers are connected to a BV7 via Ethernet, Music is coming from a BS5 also with Ethernet connection linked to the TV.

This is only happening to one of the speakers ( front right ), I disconnected them from the mains, set them to factory defaults, re-calibrated them but still humming sounds...

Any ideas from you guys?

Best regards

Stephan

Try switching the input cables and maybe even the locations where they're plugged into power (unless they are plugged into the same outlet) and see if the right speaker still makes the same noise. If the noise persists even when switching the input cables, you at least know the source of the noise is not likely to be coming from upstream in your equipment. 

Hum like that could also be caused by some type of device nearby, such as a mobile phone or other wireless device.