Merc GLK350 (2WD), soft "hooting" noise from front passenger wheel

Mercedes » GLK-Class » 2010-____
Problem Description

I have a low-pitch, soft but very audible noise coming from (I think) the front passenger wheel. It happens at low speed and faster speeds but doesn't get louder or change pitch. It more like an Owl's hoot, not a metallic or grating noise. When I touch the break it stops or if I turn the wheel left or right it also stops. It's intermittent but happening more frequently as time goes by. One shop said it's a wheel bearing but the vehicle only has 59K on it. They did no diagnosis but I did explain the symptoms and gave him my best impression of the noise. Another shop said unlikely to be a bearing, more likely a tire. A MB dealership said the same - tire more likely.