How far forward are the bars on your truck? My platform is 2.1 long so one bar is directly over my head and another not too far behind. This is where most of the noise coms from.
Maybe the air flow over the top of the windscreen is being directed into the bars. That's why I was asking about the wind deflectors as they may help direct the flow of air above the bars. Rhino do one for $119 and if it works in reducing noise and drag it would be worth it. If it's just for 'wank' factor I could live without it.