Well, when the kids are playing loudly upstairs, it rattles downstairs. I had expected a bit more from one of the top manufacturers. Fortunately, we are not that sensitive, but it is noticeable. We also have Kfw 70, which means 34cm walls; currently, I believe only the 40cm walls are available. And we hear low frequencies inside the house, for example, when a city bus passes by, we can clearly hear the humming, luckily only every 30 minutes, but from 6 a.m. on I wake up from it, whereas my wife does not, for example.