hi, did you find a solution to this? Also my speaker does not go on standby

Depending on how the audio card in the PC is designed, many things like this tend to float the ground when the device is turned off, unlike more traditionally designed hifi gear that doesn't do that. This means that when the device is off it's prone to all sorts of noise pickup that's transferred down the line to whatever it's connected to. There's a constant signal so the speakers detect it and never switch to standby.

To use a small external USB DAC would be an idea - some have their own volume control and power on/off function.

MM

That's a good idea MM, plus most outboard DACs sound better IMO, as sound cards inside the PC are subjected to extremely noisy environments with all the other digital circuitry nearby, plus most are not designed with any consideration of a good analog output stage. Most seem to be "well, we have to have an audio out, so let's just jam this cheap card in there."

An open or "uncontrolled" RCA lead is a very good AM arial.
Everything it picks up (and that's a lot of noise from all things electric) will be amplified a thousand times and put out the speakers.
Keep in mind, that the Beolab 8000 is an active speaker, it has no volume control of its own but relies
completely on an external volume control, so its input will have to be at constant max volume.

Put a switch on the RCA lead, to switch the Beolab 8000 input between the soundcard and ground, that will mute the speaker
when not "controlled" by the soundcard.

Martin