I hear a loud hum from the front end of my CR=V starting at around 60 MPH. It sounds like it is coming from under the dashboard or around the window. My mechanic drove it and could hear it (it can get pretty loud) but could not find the problem, It was intermittent but has become more frequent.
Does it change on a curve or with a twitch of the steering wheel?
I have not been able to tie it to any specific thing except speed. I almost sounds like something is loose and vibrating. At first I though it must be something under the dash.
You need to find a mechanic who has invested in modern technology, such as Chassis Ears.
None of us can hear it or experience it via cyberspace, but a good mechanic with the right equipment should be able to track-down the source of the hum fairly quickly.
Wondering if it is wind related. Could be something rattling against the firewall