"All the songs on Feels are tuned to our friends piano which was out of tune to begin with. Dave and I made loops from recordings of him playing her piano and we used those loops in the early songwriting process for Feels. So since those loops are premade and can't be tuned, the guitars have to be tuned to the loops. it's not out of tune in any tradional whole step/half step kind of way...we're talking microtonally out of tune after years of not being professionally tuned and subtle natural ...