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Studio render of a compact mini PC, a small DAC box and a bookshelf speaker connected in a line by fine cables, a sinusoid rendered as a thin copper wire above

Topic · 2 min read

The computer audio signal path

An audio signal travels through several layers before it becomes sound or a recording. Each layer has a different responsibility, making routing, format, and timing useful concepts to separate.

The bigger picture

Applications work with streams of samples. The operating system can combine streams, apply supported processing, and pass buffers to an endpoint using a format the path accepts. Hardware eventually converts playback samples to an analog signal or transmits them digitally to another device. Capture reverses the direction but still requires agreed timing and formats.

A visible volume slider is only one control within this arrangement. An application can have its own level, an endpoint can expose separate controls, and external equipment can add physical adjustments. The following pages explain the underlying roles without presuming that a changed setting is necessarily the cause of a particular listening experience. No sound needs to be played to read these explanations.

Reading map: The computer audio signal pathFirst 1 topics in reading order: The bigger picture. Each topic links to its section or page.INSIDE THIS PAGEThe computer audio signal path1The bigger picture2 paragraphs

Audio

Note these before you change anything

Useful facts to have to hand while reading about the computer audio signal path.

  • The default playback and recording devices
  • Sample rate and bit depth in the device properties
  • Enabled enhancements or spatial sound
  • Driver name and version, and whether it is a built-in class driver or a vendor one

Audio: Playback (output); recording runs the other way

  1. Applicationplays a stream
  2. Audio enginemixes and resamples
  3. Audio driverbuilt-in class or vendor
  4. Codec or DACconverts digital to analogue
  5. Speakers or headphonesanalogue or USB
Conceptual schematic of a selected path, not every request. Shown in one direction; the reverse direction uses related layers. Real systems add services, filter drivers and firmware not shown. Highlighted: the layer a driver change affects.

Pages in The computer audio signal path

Thumbnail for Playback and recording endpoints: a desktop microphone on a weighted base and a, set beside a compact mini PC, a small DAC (The computer audio signal path)Reference · 2 min read

Playback and recording endpoints

An audio endpoint is a source or destination that software can select for a stream. Playback endpoints receive sound data, while capture endpoints provide…

Thumbnail for Sample rates and audio formats: a smooth copper wire wave suspended above a row, set beside a compact mini PC, a small DAC (The computer audio signal path)Reference · 2 min read

Sample rates and audio formats

Sample rate describes how many audio samples represent each second of a signal. It is one part of a format that can also include sample representation…

Thumbnail for Shared and exclusive audio paths: three thin copper wires converging into one machined aluminium, set beside a compact mini PC, a small DAC (The computer audio signal path)Reference · 2 min read

Shared and exclusive audio paths

A shared audio path lets multiple applications contribute streams to a common endpoint. An exclusive path, when supported and requested, gives one…

Thumbnail for Audio latency and buffering: a drum pad and a speaker joined by a, set beside a compact mini PC, a small DAC (The computer audio signal path)Reference · 2 min read

Audio latency and buffering

Audio latency is the delay between an event and the corresponding sound or captured data. It accumulates across buffering, processing, transport, and…

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