Gotta take all circumstances into consideration, You could have a neighbour who works night shift and is trying to sleep during the day, and a deep thumping bass can keep anyone awake.
Sure you dont have to be quiet as a mouse, but its fair to expect to need to make compremises if you live in flats, and subs are really bad as the deep bass travels, often getting louder as it induces sympathetic vibrations in floors and ceilings.
Thumbs up to the OP who is trying to make an effort to keep his neighbours happy. You can probably have a little more volume if you keep the sub at a minimum.
As for noise laws, they are mostly guidelines, and each local council can have their own interpretation of them. There can also be local bylaws which take precidence as well, so there is no fixed >10pm <8am "rule" that works everywhere. Furthermore, if the noise is genuinely annoying the noise pollution acts can be called into play regardless of the time. If your neighbour's complain and you simply get a louder system (or turn it up), you'll likely end up with the local council, or a police officer knocking on your door.
I consider myself lucky, I have 2 foot thick stone walls, and can turn my system up to 12o'clock which is damn loud, and still the neighbours dont complain

. Although they did mention they can hear my puppy barking in the night
