50 mph hum sound. wheel bearings?

[tconnarn]

I have been hearing a humming noise from the rear of the car around 50-55 mph. it seems to be originating from the passenger side wheel, and i am thinking that it may be the wheel bearing. does this sound correct? seems like i will need to locate the SIR 90-P tool and hub removal attachments. Could it be anything else causing this noise? it sounds like someone blowing on a coke bottle.