In a house, when two rooms are next to each other, why can you hear the loud TV on the next room, despite the wall between them and despite that their two doors are closed. (I don't know a lot on physics, but isn't there something like sound travelling, does the sound travel through the wall ? It must be 3 to 5 centimetres). The loud TV is especially annoying because I hear all the bass sounds (less of the higher-pitched sounds). And I read about how just bass sound makes you anxious (especially if you are trying to sleep).
Their are two main transmission mechanism: The first one is air gaps: residential doors are not airtight and even a small gap will transmit a fair bit of sound.
The second is structure borne: The TV or loudspeaker will vibrate quite a bit and mechanically excite the surface they are resting on: the shelf, cabinet, floor, wall etc. That vibration makes it through to the next room and gets radiated by the walls, floor and/or ceiling. To a lesser extent the air-borne sound in the TV room will also vibrate other objects in the TV room (especially if the sound hits the resonance frequency) and that vibration will also end up in walls and floors.
Finally, there is direct transmission through the wall. The wall itself is also a mass/spring system which can be excited by an incident sound wave but for a decently constructed wall there is typically not a lot transmission since the wall is so much heavier than the air.