ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Beolab 28s Beolab 9s Beolab 12-3s Beolab 1s Beolab 6000s 2 pairs Beolab 4000s Beovision 7-55 Beovision 10-40 Beoplay V1 32 inch Beovision Avant 32 inch Beosound 1 (CD player) Beosound 3000 Beosound 5 Core Essence MKII Beoplay M5
Do a speaker reset. That is, unplug the speaker from the mains. Leave it unplugged for a few minutes, then replug the speaker into the mains.
Around the time that my speakers began to behave badly, this kind of thing happened as well. One of the remedies was to "reset" the speaker. Now, mind you, this symptom may also be attributed to the nasty sounds from the BL20 armageddon thread.
You mentioned your speakers made that sound once, have you had them looked at, boards replaced? If not, this might be an indicator that you should.