The basic piece of hardware needed to produce or capture (i.e. record) sound is an audio chip or sound card, referred to simply as a card. QSA can support more than one card at a time, and can even mount and unmount cards "on the fly" (more about this later). 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.
Figure 1. Cards and devices.The devices include:
You can list the devices that are on your system by typing:
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.