Audio accelerator

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An audio accelerator (APU, Audio Processing Unit ) is primarily a special digital signal processor that relieves the main processor of calculating audio signals.

There are two common methods of implementation:

AC'97

At the end of the 1990s, Intel introduced software audio drivers and chipsets based on the AC97 standard to enable inexpensive integration of the sound chip on the motherboard . However, when performing real-time calculations for audio effects (e.g. in 3D games), this solution leads to an additional load on the CPU, which can depend heavily on the number of audio channels to be calculated and the complexity of the effects ( reverb , damping , occlusion). Some software drivers reduce this additional burden by omitting effects and channels.

EAX

At the moment, only one hardware-accelerated software interface is usually supported in 3D games, which was introduced by the company Creative Labs with the soundblaster cards : the Environmental Audio Extensions (EAX).

With EAX-compatible sound chips, the spatial positions of the sound sources are sent directly to the APU, which can calculate the spatial sound changes by reading out the sample data from the main memory without CPU support.

EAX only works with Windows Vista and Windows 7 in connection with OpenAL . For older games that EAX provide via DirectSound , Creative provides the ALchemy tool.

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