If you have a 50" led light light bar then I am sure you have or are currently experiencing the whistle noise that accompanies it. So here is the reason it happens and the $5.00 dollar fix to solve it. First I want to thank "Sincityjets" for his help and assistance it tracking down the cause of the wind noise!.
First why is the noise occurring!
After a lot of trial and error and some basic engineering principles it was determined that the wind being forced up the windshield was blowing across the 5 flat fins on the back of the light bar. This was creating the same effect as blowing across the top of a coke bottle to make it whistle.
To prove this point Sincityjets taped the 5 fins and the noise went away. So the issue becomes how to break up the air blowing across the 5 fins.
So here is the 5 dollar fix, this is standard door insulation from lowes or Home Depot
You remove the the sticky tape and insert half of it I to the bottom of the flat fins like shown
And another view.
After words , just rotate it into place and the wind noise will be gone for ever! The insulation breaks up the air and prevents it from causing the whistling noise.
We hope this helps!