Driving to work this morning there was a wierd mid tone buzzing coming through my speakers in the truck. At first I thought it was the radio station I was listening to but it was still there when I turned the radio off. Now heres where it gets kinda odd... The distortion coming from the speakers only happens when I am going 65mph or higher, the higher my speed goes the louder the noise gets, I am possitive it was coming from the speakers as the subs were pulsating and I could feel them. Took one of the guys from work out to lunch today and let him try to figure out where it was coming from and he said the same thing, its coming out of the speakers and got louder as I increased the speed of the truck from 65-75mph... Any Ideas as to where it is coming from?????

 

You mentioned subs, I am assuming you have an amp. Check your ground wire. A loose or poorely connected ground wire will cause interference. If that is not the case, this may be less likely but some cell phones interfere with car audio, when my phone is about to ring I can tell in advance through my stereo. The loose ground if you have an amp is most likely the problem. Just make sure it is tight and shave any paint so that it is metal on metal. Also if that only helps alittle you may want to look for a new grounding spot. Hope this helps. Good luck.

 

Right but it is only doing it at 65+mph it wont do it sitting at a light idling or driving surface streets... Which is what is confusing the heck out of me because it will only do it then

 

That's because at low speeds or at idle, your engine isn't working as hard. The noise is most likely related to the frequencies that your engine, transmission, and all the other systems in your truck are giving off. I agree that it sounds like a poor ground. Make sure both your amp and your head unit (and any other components) are properly grounded.

 

Alternator perhaps?