An external sound card is a device that connects to a computer or other audio equipment to enhance sound quality. Unlike built-in sound cards, which are integrated into the motherboard, external sound cards offer improved audio performance and additional features. They typically connect via USB or other ports and can support various audio formats, making them popular among musicians, gamers, and audio enthusiasts. These devices often come with multiple input and output options, allowing users to connect microphones, speakers, and headphones easily. Many external sound cards also include built-in digital-to-analog converters (DACs) for better sound clarity. Overall, they provide a convenient way to upgrade audio capabilities without needing to open a computer.