What is the loudspeaker limit in residential area?

If i work out in the evening on an open roof and while I work out if i play music on my speaker. and its not too loud, its like a bit above medium. Am i allowed to do that. also its give that i don't play it between 10 pm to 6am. if its something like i have to be within a range of loudness in decibels. what is the range and how do i measure it and from where i measure it. if i measure it from a distance to the speaker, its going to come out less and if i measure it 1 mm away from the speaker it will be much more. ques2, can i record in public? not on private property, but in public areas.am i allowed to record people, police, etc. the question is if i am able to walk in an public area, can i record also, excluding sensitive areas like washrooms. or will i need permission of the people who i am recording, even if they are in public areas. also, want it clear, if a policeman stops me for some reason, can i whip out my phone and start recording him and keep recording him even if he says stop.