When you
think of 'sound card acceleration', its hard not to think of it
in video card terms, and to a greater degree this is so. Video cards
take pixel data, perform operations on that data like interpolation,
and stuff these transformed pixels out to a canvas that the game
player sees on the screen. Similarly, sound cards take raw sample
data and perform operations on that data, mix it together and then
send the result to the speakers. Some of these operations include
Echo, reflections, Doppler shifts, pitch bending and so on. The
mixer mixes samples processed by the card, as well as outside analog
inputs, like the sound from your CD-ROM drive or mics that you plug
in. There's other stuff the card does, like MIDI playback, but we
don't need to get into that for the purposes of this document.
The cool
part of the 3D sound card is what the card does with 3D sounds.
The SBLive! can handle up to 32 concurrent 3D sounds (the difference
between a 3D sound and a 2D sound is that a 3D sound has a 3D origin,
is spatialized for 4 speakers, and has a ton of clever stuff done
it after the sound is submitted to the card), while the A3D Vortex
2 chip can handle 16. On the A3D card, once a sound is submitted,
it can work out all the reflections for the sound inside a room
inside of the dedicated on card chip, which is cool, along with
all the filters required for the sound - like doppler effects, orientation
effects and so on. The SBLive! contains a programmable DSP that
works out the reverb for a sound, plus all the same sort of filters,
just done in a different fashion.
Both the
cards are pretty much the same speed - the real differences are
in what occurs physically on the card once the sound gets there.
There are some differences in approach, and in the software that
gets the sound to the card, but by and large it would be hard to
pick one over the other. As a developer, both have their good sides,
and their bad sides. It's very much a ‘swings and roundabouts’
kind of thing as to which is superior. The bottom line really is
‘how do they sound?’ Well, they both sound really good
to me, Time will tell on this one...
Of course
the one thing that Games could really use that’s not here is
.mp3 hardware decompression. We know we want it, so pretty please
manufacturers, can we have it? :)
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Jake Simpson is a code monkey for Raven Software. He's badass.
