If we go only by what is written in scripture then they do not sing. There just isn't any biblical basis for the notion that angels sing. They "shout" a bunch, so they aren't shy, so maybe they just can't carry a tune.
Also, angels are always boys, at least that is what I recall from scripture. Which makes me wonder why my partent's Christmas tree is topped by a she-angel looking like she is about to burst out in song.
Interesting little observation. Just a few comments though. First of all, you do remember that Lucifer was the angel of music? He had music flowing from him. So we know that there is at least some musical stuff going on with angels.
Also, they are referred to with the the word he, but they are not actually male angels. There are no genders within angels. Angels in reality have many heads and stuff, and that can be found somewhere in Isaiah I think. But anyhow, the cute little baby angels and perfect little women angels are all results of renasance art.
This website is cool. Lot of great thinking, and a lot I agree with you on as well.
Let all evil that remains evil unrepented, be punished equally to evils deeds. ~ God [Letters from God and His Christ - Volume 2 ~ God is Sovereign]