# Sound server

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> Markdown URL: https://mediated.wiki/source/Sound_server.md
> Source: https://en.wikipedia.org/wiki/Sound_server
> Source revision: 1354372198
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{Short description|Software that manages audio devices}}
{{About|a form of computer program that runs in the background|computers that stream audio over a network|media server}}
{{inline |date=January 2025}}
A '''sound server''' is [software](/source/software) that manages the use of and access to [audio](/source/sound_reproduction) devices (usually a [sound card](/source/sound_card)). It commonly runs as a [background process](/source/background_process).

== Sound server in an operating system==
thumb|right|Description of layers that uses a Sound Server
In a [Unix-like](/source/Unix-like) operating system, a sound server mixes different data streams (usually raw [PCM audio](/source/PCM_audio)) and sends out a single unified audio to an output device. The mixing is usually done by software, or by hardware if there is a supported [sound card](/source/sound_card).

===Layers===

The "sound stack" can be visualized as follows, with programs in the upper layers calling elements in the lower layers<ref>{{Cite web |title=Professional audio - ArchWiki |url=https://wiki.archlinux.org/title/Professional_audio |access-date=2026-02-27 |website=wiki.archlinux.org}}</ref>:

* Applications (e.g. mp3 player, web video)
* Sound server (e.g. [aRts](/source/aRts), [ESD](/source/Enlightened_Sound_Daemon), [JACK](/source/JACK_Audio_Connection_Kit), [PulseAudio](/source/PulseAudio), [PipeWire](/source/PipeWire))
* Sound subsystem (described as kernel modules or drivers; e.g. [OSS](/source/Open_Sound_System), [ALSA](/source/Advanced_Linux_Sound_Architecture))
* Operating system kernel (e.g. [Linux](/source/Linux), [Unix](/source/Unix))

=== Motivation ===

Sound servers appeared in Unix-like operating systems after limitations in [Open Sound System](/source/Open_Sound_System) were recognized. OSS is a basic sound interface that was incapable of playing multiple streams simultaneously, dealing with multiple sound cards, or streaming sound over the network. 

A sound server can provide these features by running as a [daemon](/source/daemon_(computer_software)). It receives calls from different programs and sound flows, mixes the streams, and sends raw audio out to the audio device.

With a sound server, users can also configure global and per-application sound preferences.

=== Diversification and problems ===

{{As of | 2012}} there are multiple sound servers; some focus on providing very low latency, while others concentrate on features suitable for general desktop systems. While diversification allows a user to choose just the features that are important to a particular application, it also forces developers to accommodate these options by necessitating code that is compatible with the various sound servers available. Consequently, this variety has resulted in a desire for a standard API to unify efforts.

In 2017, PipeWire began incorporating audio support, and would then go on to realize that unification for the most part.

==List of sound servers==
* [aRts](/source/aRts)
* [Enlightened Sound Daemon](/source/Enlightened_Sound_Daemon)
* [JACK](/source/JACK_Audio_Connection_Kit)
* [Network Audio System](/source/Network_Audio_System)
* [PipeWire](/source/PipeWire)
* [PulseAudio](/source/PulseAudio)
* [sndio](/source/sndio) - [OpenBSD](/source/OpenBSD) audio and MIDI framework

=== Streaming ===
* [Icecast](/source/Icecast)
* [SHOUTcast](/source/SHOUTcast)

==References==
<references />

==External links==

* [http://www.osnews.com/story.php?news_id=6720&page=2 Introduction to Linux Audio]
* [http://mail.gnome.org/archives/gnome-multimedia/2001-May/msg00002.html RFC: GNOME 2.0 Multimedia strategy]

Category:Servers (computing)

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Adapted from the Wikipedia article [Sound server](https://en.wikipedia.org/wiki/Sound_server) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Sound_server?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.