Honestly I think I would refuse a replaced chassis only when they don't even know the issue at hand. Maybe it will happen in the new chassis too. Maybe it is a manufacturing or assembly defect that is unknown. I think this is a problem in the software and just happens very intermittenly, which might be the reason it only happen in some cases only in one of the speakers. But we now know about so many different people having the issue that the problem can easily be seen as widespread. If I had animals or children I would not even have the speakers connected. This can seriously cause hearing disorder and psychological pain and discomfort in animals left alone home. 

I'd really love an official response from B&O about this issue, as it does seem to be widespread. Relatively speaking, if a handful of BL20 owners on these forums have experienced it, then it would be logical to expect that it is far more widespread than originally thought knowing that the majority of B&O owners don't even know these forums exist.

I'll say quite honestly that ever since this happened to me the first time, I've indeed been afraid to turn them on. Even to this day I hold my breath right before the logo lights turn on when I play music from the Essence.

Pardon me if I jump in here. I had the exact same problem years ago with a 2200 receiver, wall mounted with 60.2's right above bed level. More than once, always in the middle of the night I'd here the receiver 'click' on, then ramp the volume to full while playing random white noise (think fm station hiss). Using the remote or the red off button on the receiver resulted in the random noise ramping down, then back to full. It could not be turned off short of yanking the Mains. When you're sleeping and have never heard this loud of noise, so quickly, it will scare the S*** out if you. Never got a proper response from B&O or the dealer so just learned to live it, be thankfull your 20's reside on a different level.

Fast forward to now. I never wanted this type of noise to ever be an issue for me again so here is what I did: I have my Avant 55 with 9's in front, 12-3's doing surround duty in back. The 12-3's are not wireless. I did a home-run set up for all Mains cables including the 12-3 rear surrounds (Steve from Sounds Heavenly can custom make the length you need). So all Mains cables plug directly into my PS Audio P3 Power Plant, grouped but type (digital, analog, etc). Everything else with a Mains cable also gets powered from here (sat rec'v, etc). All components share the same common ground. P3 to it's own dedicated 20 amp outlet.  Overkill maybe, but no random noise of any kind (my digital dimmers were the worse offenders), because the P3 regenerates power converting AC to DC to AC all my Mains noise is gone. I don't have to worry about a Mains power spike ruining my equipment (or turning it full-on randomly), and my high frequencies are crystal clear.  I hope this helps?

Update.

Yesterday the dealer took my Beolab 20's. In both speakers, the DSP-processors, amplifiers and power supplies were replaced by brand new ones. Like he told me: "About the only thing that was NOT replaced are the speakers themselves."

So, I have high hopes the problem is solved now. Though I'm still holding my breath: if B&O isn't really acquainted with this problem, I guess they have not adjusted their manufacturing process or the design of the speaker, so it may still be a lottery ticket. We'll see - I still have two and a halve years of warranty. I'm glad I have.

One minor thing I noticed, after the replaced chassis: the speakers seem to have more treble. They sound great, but the seem (!) to sound different. Is that paranoia playing up, or could they have been calibrated differently?

jc wrote:

Update.

Yesterday the dealer took my Beolab 20's. In both speakers, the DSP-processors, amplifiers and power supplies were replaced by brand new ones. Like he told me: "About the only thing that was NOT replaced are the speakers themselves."

So, I have high hopes the problem is solved now. Though I'm still holding my breath: if B&O isn't really acquainted with this problem, I guess they have not adjusted their manufacturing process or the design of the speaker, so it may still be a lottery ticket. We'll see - I still have two and a halve years of warranty. I'm glad I have.

One minor thing I noticed, after the replaced chassis: the speakers seem to have more treble. They sound great, but the seem (!) to sound different. Is that paranoia playing up, or could they have been calibrated differently?

I´m cosidering to upgrade my BL17 to BL 20. Is this problem still occurs? Did B&O recognize the problem, recall the speakers and replace the faulty parts/speaker?

It so many questiones but I just don´t want to worry when the speaker will "explode" all the time. Thanks!

My chassis were replaced two months ago and haven't had a problem since. If even it occurs again, I will certainly post it in this thread. For now, I'm keeping my fingers crossed!

Thanks for the update. Boards were replaced in mine back in 9/2016, and it hasn't happened since. I'm confident that B&O have addressed the issue (even though there hasn't been an acknowledgment that there was an issue at all).