After a 4 month renovation, we plugged in our Playbar again. It immediately produced a very annoying high pitched sound. A complete reset to factory settings including reinstalling the sonos app did not help.
Yesterday I contacted sonos support in The Netherlands via live chat. They sent me an email with ticket number, requesting a video with clearly audible high pitched sound. From the email, it was not clear how and where to submit the video and the email address it was sent from appears to be no longer in use.
The high pitched sound from the Playbar is a known problem, but it looks like sonos is not interested in supporting older speakers. Very disappointing and unsustainable.