Very good DOF. many people hate these (as I know in a current challenge the same thing) because it is NOT ALL IN FOCUS. I think it needs just a bit more sharpness along the front of that specific key, but it is also black so it is hard to tell.
concidering the paino keys are already ebony and ivory, I think this should have been left in colour stead of b&w, it would have added a little something that I think this photo is lacking.
If I were to see this image without context it would speak of music to me, not of silence. Still it's a nicely composed image, I like angled composition and the low DOF.