Strange noise question re 2002 Boxster
 

Hi, I noticed a humming type noise which I think is coming from the right side of my car. I only hear it when I'm driving next to a wall etc. which leads me to belkieve it's on the right side. Whether I'm in gear or neutal it's there but it stops exactly at 25mph. Is it possible it's just a wind noise perhaps thru the side vent I'm hearing. Could it be my tires which seem fine and have less than 10k on them. My car is a 2002. I thought wheel bearing but it clearly stops exactly at 25mph. Its somewhat high pitched. Thanks.