I know that I am not a good singer also, but that is why I sing only at decibels only audible to myself or if the water coming out of the shower is strong enough to drown out any unpleasant ambient noise that might reach you. Why? Other than the first reason stated, I believe that being a good neighbor not only means you have to be tolerant of your neighbors, but considerate of them also. Goodness! We have been tolerant enough. Could you please be more considerate of others?
Singing from 8.00am until 11.30pm everyday, seven days a week with full microphone volume is just not done when you CANNOT even carry a tune. I would have no qualms about this if your voice was good enough that it was recorded and that recording was a multi-platinum selling album. Heck, even singers preserve their voices and keep long periods of silence. Wait! Oh, yeah, this just cements the fact that you are MOST DEFINITELY NOT A SINGER! And you encourage your little posse every night to do the same too!
If we were in the US they'd grow rich from the number of times they would've slapped you with a fine for disturbing the peace.
Really, is peace and quiet too much to ask by 9:00pm so that your neighbors can get a good night's rest everyday?
I wish God had given you a better ear for music so that you'd realize how tone deaf you and your cohorts really are. Maybe then, you would find another, ACTUAL GOD-GIVEN TALENT.