Lyric discussion by Hick 

Cover art for Trani lyrics by Kings of Leon

To me the debate on Trani is quite simple (I may have it wrong) however in Oz we call an old radio a trani (from transister radio). So a trani has a tinny sound anyway, thus in a tin shed or on a tin roof sounds even worse. Hence "a white noise sound, like a trani on tin".

Dude he's talking about trani- a transvestite on drugs