There is a frequent sound from bottom or front of the bike.The frequency is higher when speed is higher. Progress with the speed. It doesn't mater what gear it is or neutral.I thought the is a problem with breaks or bearings but when I wheel the wheel I can't hear anything? Can this sound be from somewhere else then wheel.
Not really precise enough, but have you recently done any work on the bike?
Could well be the bearings, but binding brakes can cause this too, even when applied. Had that recently and just standard post-winter clean sorted it. Suggest give em a clean at same time as inspecting your bearings.Andy