Every good band has its own signature sound, or at least most of them probably do. It's instrumental (pun intended) to the brand, it's key to their aesthetic, and it creates a certain level of expectation from the group's devoted fans. When we think of popular musicians, we can think of a song that pops into our heads that basically sums them up. Of course, not every piece should sound the same; there has to be a little wiggle-room to expand and keep things feeling fresh. That's the nature of art, but every now and again a band will naturally go well outside of their comfort-zone.