My car has 75,000 miles on it and seems to have recently developed a noise that I can only describe as a subtle motorboat sound. I notice it mostly at around 45-52 mph but it seems to be present at all speeds. The local dealer replaced my tires last year and said they upgraded to a better and quieter tire. We’ve looked at the tires and we don’t see anything amiss. It seems to be emanating from the front of the vehicle and the frequency correlates with my speed. People with hearing issues don’t notice it. Any ideas on what it could be?