DirectSound is a deprecated software component of the Microsoft DirectX library for the Windows operating system, superseded by XAudio2.
[2] After many years of development, today DirectSound is a mature API, and supplies many other useful capabilities, such as the ability to play multichannel sounds at high resolution.
If hardware acceleration is not available, DirectSound would create audio buffers in the system memory and use purely software mixing.
These cards featured local memory which could be used for buffering multiple audio streams and mixing them on board, thus offloading the CPU and greatly improving the sound quality.
Later cards such as Sound Blaster Live!, Audigy and X-Fi are capable of accessing the system memory buffers directly.
In DirectX 5, DirectSound3D gained the support for sound cards that use third party 3D audio algorithms in order to accelerate DirectSound3D properly, through methods approved by Microsoft.
In Windows 95, 98 and Me, the DirectSound mixer component and the sound card drivers were both implemented as a kernel-mode VxD driver (Dsound.vxd), allowing direct access to the primary buffer used by the audio hardware and thus, providing the lowest possible latency between the user-mode API and the underlying hardware, but in some cases causing instability and blue screen errors.
Due to internal buffering, KMixer introduced significant processing latency (30 ms on then-current systems).
[6] In Windows XP, Microsoft introduced another improved kernel streaming class driver, AVStream.
[9] Third-party APIs such as ASIO and OpenAL are not affected by these architectural changes in Windows Vista, as they use IOCtl to interface directly with the audio driver.
[14] Windows CE 6.0 also does not support DirectSound, instead favoring that applications be rewritten to use the Waveform Audio API.
Realtek, a manufacturer of integrated HD audio codecs, has a product similar to ALchemy called 3D SoundBack.