PC audio started with the internal speaker and evolved through AdLib's FM synthesis and Creative's Sound Blaster to today's diverse ecosystem. Modern audio hardware includes integrated motherboard codecs, internal PCIe cards, and external USB or Thunderbolt interfaces that support high-resolution recording and low-latency workflows. Standards such as the USB Audio Device Class and OS audio APIs unify device compatibility.
What sound cards are
Computer sound cards are expansion devices - internal cards or external interfaces - that let a computer input and output audio under software control. They power music production, video and audio editing, games, streaming, and voice chat. Today many systems use integrated audio codecs on the motherboard, while enthusiasts and professionals often add dedicated PCIe, USB, or Thunderbolt audio interfaces for higher fidelity and lower latency.
Early PC audio: from beepers to synthesis
Early IBM-compatible PCs used a simple internal speaker that produced basic square waves. Software could generate melodies and effects, but the sound was limited and nicknamed the "beeper." In the late 1980s manufacturers began shipping add-in sound cards that provided much richer audio.
AdLib released one of the first popular PC sound cards, built around Yamaha's YM3812 FM synthesis chip (OPL2). That card let games and music software play multi-voice synthesized music instead of simple beeps.
The Sound Blaster and the rise of digital audio
Creative Labs' Sound Blaster series became the dominant PC audio standard by cloning AdLib's FM compatibility and adding digital audio recording and playback, a joystick/game port, and MIDI interfacing. Its broad software compatibility and extra features made the Sound Blaster a common first choice for multimedia PCs.
Bus architectures and duplex capabilities
Older ISA sound cards were often half-duplex (could not record and play simultaneously). Later ISA models and PCI cards added full-duplex support. PCI and modern PCIe internal cards generally support simultaneous recording and playback without the IRQ and DMA constraints that early ISA cards faced.
USB, Thunderbolt, and external audio interfaces
A major shift has been toward external audio devices connected by USB or Thunderbolt. USB audio adapters and professional USB/Thunderbolt audio interfaces offer convenient connectivity and standardized drivers. The USB Audio Device Class (UAC) lets many USB audio devices work with a single driver model; UAC 2.0 expanded support for higher sample rates and bit depths and is widely used by modern interfaces.
External interfaces from makers such as Focusrite, RME, and others provide balanced analog I/O, microphone preamps, and low-latency operation for recording and live performance.
Integrated codecs and modern software
Most consumer motherboards ship with integrated audio codecs (often from vendors like Realtek) compliant with standards such as Intel High Definition Audio. Operating systems expose audio through APIs and drivers such as Core Audio (macOS), WASAPI or ASIO (Windows), and ALSA/PulseAudio/pipewire (Linux), which handle mixing, routing, and low-latency access for pro audio applications.
Where audio hardware stands now
Internal PCIe cards still serve niche needs (high channel counts, specialized DSP), but many users choose USB/Thunderbolt interfaces for flexibility. HDMI and Bluetooth also carry digital audio for displays and headsets. The sound card concept endures, but its forms and interfaces have diversified to match modern workflows.