Whirring/Humming Noise?

I recently purchased a used 2006 bmw 330i.
Everything is about the car is great, however, there is a very annoying whirring/buzzing noise. The noise dies down at high speeds, but it is very obvious at low speeds.
The noise is there even when the a/c is off, and fluctuates with different rpms, its really loud during idle and initial acceleration. Iv sat in my friends 328 and there is no noise at all.
Anyone know what the problem might be before I take the car to a mechanic?

Originally Posted by banyehaozi

I recently purchased a used 2006 bmw 330i.
Everything is about the car is great, however, there is a very annoying whirring/buzzing noise. The noise dies down at high speeds, but it is very obvious at low speeds.
The noise is there even when the a/c is off, and fluctuates with different rpms, its really loud during idle and initial acceleration. Iv sat in my friends 328 and there is no noise at all.
Anyone know what the problem might be before I take the car to a mechanic?

Post a YouTube.

Could it be your engine?