my car is making a weird noise

I have a 2000 Honda Civic and it is making a high pitched hum when I reach 70mph. Then after I get below that it stops. Does anyone know what this might be about, and how I go about fixing it?

Try getting your wheels/tires balanced, an imbalanced wheel could cause vibration at certian speeds leading to a humming sound.

Might be one of the wheel bearings. If it's a front wheel bearing your best bet would be to have the dealer take care of it because the old bearing will need to be pressed out of the knuckle and the new one pressed in. If it's a rear wheel bearing a handy person can remove most of the brake hardware (if an Si, if not all you need do is remove the brake drum), take the hub nut off, and replace the bearing as a unit. GL

Do you still have the stock tires on it?