[Openal] Some Newbie Questions

[dpeacock at creativelabs.com]

Hi Chris,

1. Sound source distance from listener
2. Sound source direction from listener
3. Sound source directivity
4. Doppler shift for moving sound source
5. Additional effects (EAX)

The Windows implementation of Open AL includes two different backends or
'devices'.  The "Generic Software" device does all of the above in
software.   The "Generic Hardware" device does all the above in hardware.
Depending upon what soundcard / soundchip you are using, will determine
which device you can use.   The "Generic Hardware" device can only be used
if the sound solution supports at least 16 Hardware Direct Sound 3D
buffers.

>Also, am I right in saying that EAX 2.0 is supported by most audio
>hardware however only Creative hardware supports EAX 3.0 and higher?

Yes that is correct.

Dan

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             Chris Share                                                   
             <cshare01 at qub.ac.                                             
             uk>                                                        To 
             Sent by:                  openal at opensource.creative.com      
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             source.creative.c                                             
             om                                                    Subject 
                                       [Openal] Some Newbie Questions      
                                                                           
             10/25/2005 03:49                                              
             AM                                                            
                                                                           
                                                                           
                                                                           




Hi,

I'm new to OpenAL and have some questions about how it works. I'm using
a Windows XP laptop with the built-in audio output device.

 From my reading of the OpenAL docs, the API simulates the following
effects:

1. Sound source distance from listener
2. Sound source direction from listener
3. Sound source directivity
4. Doppler shift for moving sound source
5. Additional effects (EAX)

What I'm unclear about is how the processing listed above is being done,
and where it takes place, that is, does it take place in software or on
the soundcard itself.

My guess is that 1, 3 and 4 are being done in software. What about 2
(which probably relies on some sort of HRTF calculation)? Also, what
about 5?

Also, am I right in saying that EAX 2.0 is supported by most audio
hardware however only Creative hardware supports EAX 3.0 and higher?

Cheers,

Chris Share


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