The passive speaker trembled loudly enough at low frequencies. In other words, the case's sealing is compromised (without affecting the phase inverter's opening). And it wasn't on the one that was in use. I had to use sealant to go through the connector's joints and along the borders of the backplate (with the entry). I used sealant to treat the phase inverter as well. The deficiency wasn't fixed until all these procedures were completed. Link to a demonstration video
Sangean PR-D4W Portable Weather Alert Radio with AM/FM Bandwidth Narrowing and Auto Tracking for Improved Searchability
12 Review
AUNA Connect 150 Black 2.1 Wi-Fi Internet Radio Music Player With MP3 USB Port, AUX & Remote Control - Black
16 Review
Sony ICFC1TBLACK Alarm Clock Radio
11 Review
Radio receiver Max MR-322 anthracite
14 Review