2003 Chevy Cavalier Engine makes noise when accelerating

Hi. I have a 2003 Chevy Cavalier, 96000 km's on it. When i was driving to work today I heard a humming noise in the front right side of my engine. It would get higher and louder as I accelerated. It almost sounded like a harmonica being played as I accelerated. It was very loud inside the car, I thought something inside was making the noise, but it seemed to be coming more from the dash on the right hand side, or maybe the top right of the engine. It was not a high pitched whirr or squeak, it sounded like a harmonica getting higher as i accelerated. Idling no sound. Sound would get lower as I braked.