PLEASE HELP With Roof Light Bar Whistle

I put a 50 inch curved light bar on MCM roof brackets and I can not for the life of me stop it from whistling. I get the whistle above 20mph, then it turns to an awful harmonic noise at highway speeds. I tried the door trim on the bottom 4 fins and it made no difference at all. I tried taping off all the fins so the back was sealed and it still whistled. I tried mocking up a cardboard fairing for it (below) which stopped the highway speed noise, but the whistle around town is as bad as ever. I can't think of anything else to do! Anyone have suggestions, or want to make an offer on this damn light bar?

 

take off the light and leave the brackets on a test run, they might cause some of the whistle too.

You could always fab up a Plexiglas guard around it and see if that helps, The air under the light bar should not be the whistle issue.

 

pm me if you decide to sell the bar
or the mounts at least!

 

Okay. I drove it around without the light bar and the mounts on their own are quiet as can be. I picked up some irrigation hose to cram in there as some people have done, although I don't see it doing much if the door trim didn't help. I'll report back shortly!

 

Roof light be whistle pretty common. Got them on several work trucks, since then guys all have taken em off as couldn't handle it and simply got too annoyed.

Good luck.

 

Just add one of these wings to the top of it... duct tape it.

 

That sucks... and is exactly why I've held off doing that for fear it would be too noisy... probably the shape of the light... too bad someone doesn't have one made to be quieter and mounts that bring it back a bit more might help...

 

I put some 1/4in irrigation hose in between the fins in 4 inch strips , at both ends and the middle. I also still have the door trim on the bottom 4 fins. Not any better.

Why the top fin? I'll give it a go I just don't see the theory behind it.

I picked up a bunch of washers. I'm going to try using them as spacers to raise the mount a bit and see if that helps.

 

The bar is compressing airflow. Air is moving up the windshield and under the bar and goes into high pressure.

I'd create a Lexan fairing and mount it to the bottom on the bar... minimizing the volume of air compressing under the bar.

 

Go to a hardware store buy some roll insulation 1/8 and squeeze them in the housing of the light bar will stop it for sure in each row also we place door weatherstrip from the bottom housing of the bar to the roof and it helpes.

 

My 50" Rigid light came with (3) of these. I used (2) of them equally spaced out on the back and have no whistle at all. But when the wind is blowing really hard I can hear wind noise, but no whistle. Might work for you..

http://partners-rigidindustries.com/images/EseriesResonanceDamper.pdf

 

Thanks guys. I tried using some washers to move the light bar further from the roof... but it actually made it worse. I'll try some more of your ideas tomorrow

 

Like so?

http://www.tacomaworld.com/forum/lighting/352236-how-fix-light-bar-whistle.html

 

Below is your answer. Put this on your first on the list to try. The whistle comes from the top fin or the bottom fin typically. Mine whistled horribly.

 

Cool. I'll start with door trim on the top fin (or two). I might even find some time tonight if I feel like working in the dark.

 

telling you... this is the answer. so much hipper too...


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Today I tried door trim on the top fin, every combination of door trim and irrigation hose possible, and experimented with different heights and angles. I've come to the conclusion that it's the wind between the truck and the bar that's making the harmonic noise on the highway and I found a nice height that reduced that a lot... the whistle is still as bad as ever though. Really confused. I'm getting used to the whistle now and it doesn't bother me much with the radio on.. I'm going to try dynomat on the roof to see if I can just block some of the noise out. Should help with the vibrations in the harmonic noise as well.