New Sound Technology for PCs

New Sound Technology for PCs
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Let’s consider how these tools could be applied in an imaginary game. Suppose there are a couple tanks in the game. One is idling, the other is moving. Let’s download these sounds using DirectMusic and use the wavetable synthesizer to render them. DirectMusic permits us to specify one sample for the tank sound. Playing the sample at its original pitch produces the engine idling sound. Playing it at an elevated pitch produces the sound for the tank that is moving. The wavetable synthesizer also allows us to loop the sound so that a short snippet suffices. A jet flying overhead is approaching from behind us. DirectSound3D permits us to specify the nature of the sound, its position, and its velocity so it actually seems as if the jet is in the correct position. That cue might be the clue to turn our tank so that we can fire at the jet. A further refinement of DirectSound3D is its Doppler shift parameter, which makes it possible to shift the pitch of the jet sound as it flies by. A tank fires. The sound could be another sample downloaded using the DirectMusic API permitting it to be triggered using a MIDI Note On command. A more distant firing is created by the same sample but with a Note On command that specifies that it be played more quietly.

There is musical accompaniment because music heightens the emotional impact. The composer selected the sounds that he wanted to use in rendering the score and downloaded them using the DirectMusic API. Thus, the composer’s creative opportunities encompass not only the musical composition, but the sounds of the instruments as well. The audio subsystem applies spatial enhancement to broaden the stereo sound stage, which increases the impact of the accompaniment.

The unlocalized sounds inside the tank are rendered using DirectSound. Some are speech, so their sample rate is low (8 kHz). DirectSound makes sure that they are up-sampled so that they can be mixed with the musical accompaniment (44.1 kHz) as well as the other sounds. While all this audio processing is happening, we also have graphics rendering taking place. It’s amazing how all this multimedia action comes together to create an engrossing and enjoyable game-playing experience.
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