The basic piece of hardware needed to produce or capture (or record) sound is an audio chip or sound card, referred to simply as a card.
All the sound devices are attached to a card, so in order to reach a device, you must first know
what card it's attached to. The following diagram shows cards and devices:
The devices include:
You can type the following command to list the devices that are on your
system:
ls /dev/snd
The resulting list includes one control device for every sound card, starting from card 0, as well as the PCM and mixer devices for each card.