From one of beolab 4000 connected to ouverture I hear a very faint hummmm, almost like a wavy Sound almost like the sound you hear when the tape is running but empty with no track. One thing I noticed is if hold the power cord or metal part of beolab the noise vanishes. It's coming only from one Speaker. What could be wrong. The hum is only audible at very very close to speaker

Try switching the cables from one speker to the other. If the hum is present on the other speaker, then it's your cables. If the hum remains on the original speaker then you'll have to take it to service...

sounds like cables though

Agree with our member down under: Sounds like the cables.

A pulsating,  or " wavy " sound would indicate electrical source interference, through the cable, or from a nearby source.

In addition to the good comments above, you might also consider checking the switches in the back of each of your Beolab 4000 speakers (L-R), and also trace down your main electrical source for proper grounding.

Nice avatar.

Thanks for all the good input.

What did u mean by checking the L/R buttons. Is it to make sure that both are not on L or R.

Thanks

Beocom 6000 was the reason, it was too close

Good to hear you identified the source.