I want to learn to play the Trumpet, but wondering how loud it may be at home ? I'm living in a flat (neighbours up and down)
It depends entirely on where you live. Different countries and different residents' associations have different rules.
For instance in the apartment project where I live the only restriction is that I must not make noise between 11pm and 7am. There are strict decibel limits and we can download an app which will measure noise coming from a neighbour's apartment and use that for a formal complaint.
There was actually a German court case 2 years ago involving a trumpet player. The court ruled in favour of the trumpet player within certain limits. Here are the key points:
Neighbours must put up with a certain degree of noise from neighbours who play musical instruments, saying that the practice times are "socially acceptable and common forms of leisure time activities."
A quiet-time compromise must be struck with neighbours, however, and depends entirely upon the type of instrument used.
The court recommended a general rule of limiting practice times to two to three hours on weekdays and one to two hours on Sundays and holidays.
Judges also emphasized that the standards they set apply equally to amateur and professional musicians.