Have you had your car tyres changed recently.
I once had my tyres changed and almost immediately after it started making this awful noise everytime i turn. I went back to the tyre place and they insisted it was not the cause.
I had the belt changed, oil change, all sorts of repairs with no luck.
One day i had a flat tyre and called the AA to help. They then found out that when u had my tyre changed they had put an incorrect rim and insisted that i change it.
The minute this was changed, the noise stopped.