Re: OpenAL sources - volume issues

Thanks for the reply Chris! Someone else looked into it further, and it does indeed seem to be an issue with how Apple's implementation of OpenAL uses CoreAudio to handle the mixing. He can describe the issue better than I can. However, even in looking at the source code, he doesn't seem an obvious fix. :-/

I will definitely try out OpenAL Soft! Thanks.

-Vern

On Aug 5, 2011, at 10:30 PM, Chris Robinson wrote:

> On Friday, August 05, 2011 6:09:34 PM Vern Jensen wrote:
>> I've done more testing this, and it's better explained like so:
>> 
>> 1) Play a sound in an OpenAL source at a high gain, like 1.0.
>> 2) Once the sound has finished playing, play a different sound in any source
>> at a very low gain, like 0.01.
>> 
>> The new sound will *not* play at the specific 0.01 gain, but will rather
>> start at the 1.0 gain and "slide down" to the proper gain setting. For very
>> short sounds, like button clicks, this results in the next several click
>> sounds coming out at, say, 1.0, 0.7, 0.4, and finally 0.01 gains. (These
>> values are estimates of what it sounds like to my ear... I don't know the
>> exact gain they are being played at.) For longer sound effects, the sound
>> starts at around 1.0 gain and quickly slides down to 0.01 within a fraction
>> of a second, but slow enough that you can hear it.
> ...
>> This is on MacOS X 10.6.8. I haven't verified if this happens on other OSes.
> 
> I've heard of this issue before on OSX, but unfortunately, am not aware of any 
> fix. It doesn't happen on other OSs, as far as I'm aware.
> 
> One thing I can think of... instead of reusing the sources, try deleting them 
> when no longer in use and generating a new one when you need it. It'll be less 
> efficient that way, but perhaps it'll work around the problem.
> 
> Another option would be to try OpenAL Soft, although you will need to build a 
> recent version from Git/SVN for proper OSX support.
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