Your phone is likely focusing on the drum head an over-exposing for some reason. Two suggestions:
Try getting the phone to take its reading elsewhere in the image (not sure how to do that).
(If I was shooting with an SLR I would experiment with different focal points to get the right exposure. I have this problem when trying to photograph things on the fascia and the layout itself comes out over-exposed - always a challenge when trying to incorporate two different light levels in the same image.)
Try taking the photo on an angle to the coach so the drum head will not be as bight.
Tim