Quiet roof rack?

I’ve got yakima round bars
with a j rack on one side and a v cradle on the other and they seem to make quite a racket—what is the secret to making them quieter

My Experience
Round Yakima bars = very loud roar.



Thule square bars = mildly annoying whistle.

wrapping with string also worked for me
Thank you Jack for the idea about covering the end of the tube. Yakima also makes a front wing- air deflector- that might work. About racks, I have 4ft of span with my yakima racks on a taurus- after I pop riveted up thru door frame thru the clips. You need oil on a super drill to drill tough steel on yakima clips. Great to have no stress of going 70 on the freeway with a boat for 1000 miles. Span is the key to a long boat. Also you can make canoe clips by wrapping hose clamps around a 2in cube of wood. Put on each corner of canoe.