Yeah, I did notice that. But still, given the proximity and materials used in the build, if a HM goes into the Diary Room in the early hours of the morning or dead of the night, surely you’d be able to hear something between the HM and the BB speaker.
If ex HMs in the marathon streams were saying you could hear things from the Diary Room through the walls in 2006 and 2007 (and there’s that clip from 2001 where they’re shouting task answers from the living room), then I’d say some soundproofing in this cheaper structure isn’t gonna do a lot.