Actually not only HDB estate, on buses and MRT trains as well. There are just many people who are inconsiderate... young, old, local, foreigners and etc... they seem to have "hearing" issue and like to listen to loud music or drama on mobile phone...
It seems that the peaceful and quiet days are gone...
https://sg.news.yahoo.com/disruptive-bus-passengers-those-play-145727239.html
Now public transport law can fine them for it .... but no iron in them to also implement same law to housing estate noise.