Hey. I was thinking that it would be cool if the 11th Doctors 1st Tardis would have the 2010 Tardis hum. 
https://www.youtube.com/watch?v=AZVquKHvtSk
It also sounds cool for any type of Tardis 

the default hum is just that, just without those strange bell(?) sounds

Yeah im talking about the strange bell sounds