This plastic and metal thing is called a soundcard. It's like a musician, really. The CPU tells it what music or sound to play and it sends the sound to your speakers or headphones - whatever is plugged into your computer. Many computers don't actually have one of these because they are often a part of the motherboard (making the motherboard quite a talented device). It always found inside that beige box, so you might not have seen one before.  ¶ 12:40 AM