[Openal] Can someone explain signed vs. unsigned audio

[Jason Daly]

Kyle D. Jansen wrote:
> Then what is the difference between signs, since, as far as the bits, [signed] -128 == [unsigned] 0?
> Further, how is volume heard? ie, is -127 as "loud" as 127? I'm doing calculations with the psychological volume, and I want to be clear on this.
>   

To get the basic idea, you can relate the sign of the sample to the 
movement of a loudspeaker.  -128 means the diaphragm is all the way 
"in", whereas +127 is all the way "out" (or vice versa).

As far as "loudness" is concerned, I think the sign is irrelevant, but 
I'm not sure.  I suppose you could look at the literature and see if 
humans perceive positive and negative sound pressure differently.  I 
doubt it, though, and most likely you can just take the absolute value 
and use that it your calculations (don't quote me in your paper, though 
:-) ).

--"J"