All about Aureal's technology including the APIs (A3D 1.0, 2.0, 3.0), sound cards, chips (including the Vortex 2 and Motorola DSP), speakers and anything else you can think of with respect to Aureal's technology. For support questions check out our support FAQ.
The stream routing in Vortex 2 is completely programmable. Vortex 2 features 96 DMA streams. These streams are audio data streams going from host memory down to the chip. 32 of those streams can additionally also go in the other direction, i.e. from the chip back up to host memory. Once an audio stream is inside the chip it is routed along the internal 'Vortex Dataflow Bus' to go between the various core audio processing engines (sample rate conversion engine, mixer engine, 3D engine, wave table engine, etc.). The Vortex 2 driver software decides how to route the streams based on user settings and the real-time audio needs of the various applications running on your PC at any given time. Since no connections are hardwired, the chip has great flexibility that translates into optimal usage of hardware resources for any given task and the ability to re-program the data flow for new tasks. An example of the latter is multi-channel Dolby Digital streaming support which was recently integrated. This architecture also makes Vortex 2 a great fit for the upcoming WDM (Windows Driver Model), which is heavily oriented towards stream routing. As far as I know, the Vortex architecture is unique in terms of combining highly optimized core audio processing engines with complete topological flexibility to route sound streams between those engines. Having mastered the complexity of such a design, we are now reaping the benefits by having a solution that can deliver maximum quality at minimum silicon cost (BTW, both Vortex 1 and 2 are based on the same core architecture). Other PCI audio chips are usually either general purpose DSP based, hardwired, or hybrids of hardwired Wavetable engines with audio effects DSPs on the side.
If you are looking at actual usage scenarios, things get complicated quickly. The basic rule is that Vortex 2 can handle any form of audio stream and multiple active streams can add up to 96 at any given time. Of the 96 streams, 4 are pretty much permanently allocated to overhead such as the DirectSound primary buffer, or line and mic input. That leaves 92 output streams. Of those, you can have a maximum of:
92 DirectSound (i.e., they can all be DirectSound if necessary)
76 3D streams (they can be A3D, DS3D, or A3D 2.0, in the case of A3D 2.0, they are currently split between direct path and reflective sounds (16+60))
64 Wavetable voices
The different types of streams can be mixed and matched in various ways, but they always have to add up to a maximum of 96.
There are other types of streams such as wavOut, or DOS legacy apps, of which you'd typically only ever have a few running in parallel at the most (Vortex 2 can handle them as well of course).
A typical usage scenario for today's applications might be:
You are playing an A3D game that uses 16 A3D channels for primary sound effects, 2 DirectSound channels for soundtrack streaming off a CD, 8 DirectSound channels for background effects. Additionally, you have e-mail running in the background which uses a wavOut channel to play an e-mail alert sound every once in a while. This would add up to about 32 streams (with overhead channels).
Such a game could add another 32 A3D or DirectSound3D channels, and still be well within the limits of Vortex 2 (64 streams).
Or for more advanced uses, you might imagine that a (future) game adds 32 3D reflections to the baseline described above, and has a DirectMusic soundtrack that maxes out at 32 voices. This would bring you to about 96 streams and take advantage of the entire Vortex 2 chip. - Updated: November 29, 1999
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