I would say 9am at the very earliest on a Sunday.
But depends on the variables.
How close your house is to other neighbours.
Location - estate noise reverberates.
Shriek/scream factor - do you have relatively quiet kids or shriekers?
Location of equipment - is the play equipment (same for bbqs etc) as far away from your house/back door as possible but nicely nearer to yr neighbours so they get more of the benefit.