1
We could hear a very good music coming from the room.
We could hear very good music coming from the room.
Music is an uncountable noun, so do not use a/an before it: ‘good music’, ‘some music’, ‘beautiful music’.
To talk about one musical work, use a piece of music: ‘We heard a beautiful piece of music.’
2
I like all kinds of musics.
I like all kinds of music.
Music does not normally have a plural form. Use music, not musics: ‘different types of music’, ‘all kinds of music’.