[Openal] m-audio quatro and openAL

[Daniel PEACOCK]

Hi,

Sorry the for the delay getting back to you - I've been sick for the last
couple of days.

ASIO is obviously designed for music applications to use for super low
latency on playback.   I'm no expert on how the ASIO features of our cards
work - but I believe you have quite flexible routing options on how the
audio outputs are configured. I would imagine it is pretty similar to your
M-Audio card in that you can configure an audio track to pan to any of the
discrete outputs.

OpenAL is designed for 3D Audio applications.   In this case, it is
important the soundcard is correctly configured in either the X-Fi's own
control panel (preferable) or the Vista Sound Properties page.
Specifically you need to pick the right speaker mode (Headphones*, stereo,
quad, 5.1, or 7.1) and ideally you should put the soundcard in Game Mode*.
Items marked by * can only be set in the Creative Software applications -
which is why it is best to use them instead of the Vista Sound properties.

In OpenAL you can either playback 3D positioned voices which are then
virtualized in a manner appropriate to the playback configuration (because
different 3D algorithms are used to render the audio for each different
speaker mode).    OpenAL can also playback multi-channel wavefiles and
these will be played on the appropriate physical speakers or virtualized if
a specific speaker doesn't exist (e.g if you play a 5.1 wavefile when the
soundcard is in quad speaker mode the front center will be mixed into the
front left and right.

The OpenAL driver for X-Fi cards, like ASIO, features very low latency for
playback and parameter updates.

Dan
Creative Labs (UK) Ltd.

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             Jason Daly                                                    
             <jdaly at ist.ucf.ed                                             
             u>                                                         To 
             Sent by:                  Yvan Vander Sanden                  
             openal-bounces at op         <yvan at youngmusic.org>               
             ensource.creative                                          cc 
             .com                      "openal at opensource.creative.com"    
                                       <openal at opensource.creative.com>    
                                                                   Subject 
             01/12/2009 06:48          Re: [Openal] m-audio quatro and     
             PM                        openAL                              
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Yvan Vander Sanden wrote:
> I'm using Windows Vista. The Windows XP drivers from M-Audio work on
> vista for all applications like Sonar and Pure Data, so that should
> not be a problem. As of this morning, I've convinced myself to by a
> buy a SB X-Fi titanium from a local store and it seems to work pretty
> well. I am a bit anxious about latency though, and the mini-jacks are
> always prone to defects. So I'd still prefer to use a more
> 'professional' audio card since the application i'm writing is
> intended for live performances.
>

Just a quick note here.  Some of the nicer X-Fi cards have either a
drive bay panel or an external break-out box with 1/4" jacks (assuming
these haven't been totally discontinued, I haven't looked in a while).
As for the latency issue, most of the good X-Fi cards come with ASIO
drivers (which Sonar should be able to take advantage of).

The biggest problem here is that Creative puts the X-Fi name on
everything, so you have to do some digging to figure out which cards
have the high quality hardware (the EMU20K1 chipset), and which ones are
just pretending.


> The question I asked might be more general: consumer audio cards do
> have specific outputs for Front and Rear speakers, but professional
> audio cards just have 4 or more outputs. So how to assign them?
>

It's going to depend on your OS and audio card drivers (which is
probably why Dan asked).  OpenAL hasn't converged on a standard way of
handling multi-channel output (let alone input), so various
implementations will handle it in various ways.

I'm not sure how the Windows implementation handles it, so I'll defer
this to someone more knowledgeable.

--"J"

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