you adjust the steering head tube's bearings?
these can be hard to get right.. depending on the bike there might be a nut and a lock nut above it.. Although the locknut feels tight the one underneath may be loose.
cause it sure do sound like that steering head is loose.. and something in or on the front end vibrates, like a fender or shock absorber component.. and it's making the actual noise.
BTW, if the bearings do need adjustment you'd tighten the nut till there is no slop.. but the wheel can easily move left and right with no resistance.