Mosques in The Hague are not allowed to sing etc for prayer, and that is for their own safety
I actually went to take a look for the house and service (or how is that called for muslims) was just over, I can assure you, I have never met people more polite then those people in the entire city of The Hague
most of them greated me, 2 young guys asked if I was looking for something and if they could help
and I even got invited in for some tea (and really delicious biscuits) by some women (I was biting my time there, I had to wait for like 45 minutes for my ex)