We just learned about the Hard Drive.
Another part of a computer is a Sound Card also called an audio card or audio interface.
When computers were first made, about the only sound they could make was a BEEP sound.
Then later they were able to make different beeps that could make music.
Eventually people wanted to actually play songs or watch shows on their computers and hear actual sounds.
Most old computer motherboards couldn't do that, so people had to buy a thing called a sound card that plugged into a motherboard.
These days most computers can play music and sounds for movies without having an extra card that has to be plugged in, but sometimes professional people that are making music or movies want to have even better sound might still need an extra piece of hardware to make it better.
(from: wikipedia - sound card)
Kid Facts - Blast from the past: Coupling