Nintendo DS Architecture: Novel Forms of Interaction by Rodrigo Copetti

Author:Rodrigo Copetti [Copetti, Rodrigo]
Language: eng
Format: epub
Tags: Nonfiction, Computers, Advanced Computing, Engineering, Computer Architecture, Application Software, Computer Graphics, Computer Science
ISBN: 9798201403621
Amazon: B0B65V1Y9X
Goodreads: 62908902
Published: 2020-08-10T16:30:00+00:00

6.1 An eccentric PSG (or two)

Since this console runs GBA games, it should then have something that reassembles the predecessor’s PSG (whether through hardware or software). Well, it so happens the last 6 channels contain a ‘PSG mode’ allowing any of them to synthesise either a pulse or a custom wave; and only two of them can create noise. But GBA games don’t use any of these!

You see, the mixer’s output frequency rate is 32 kHz with a resolution of 10-bit (considerably lower than the quality of the samples fed). Furthermore, it does not perform any form of interpolation to smooth out the loss of precision. These restrictions are not ideal for samples, as it adds noise. Though the actual perception of this phenomenon depends on your auditory capacity (I don’t notice the ‘hiss’ unless I boost the volume and compare it with a 16-bit version side-by-side), besides, it’s still a step forward coming from software-mixed samples with 8-bit resolution. Conversely, the aliasing effect is more problematic with PSG sounds, as downsampling the signal may introduce erroneous harmonics which distorts the original PSG tone. Nevertheless, games like New Super Mario Bros. happily make use of pulse waves for accompaniment, so I wouldn’t consider the PSG completely useless.

Back on topic, how does a GBA game handle all of this? It doesn’t, Nintendo fitted a separate sound system (within the same enclosure) for GBA mode that includes its own channels and mixer that follows the specifications of the predecessor. This way, GBA games won’t be affected by the new mixer’s limitations. Unfortunately, since this subsystem is segregated from the DS one (in other words, it doesn’t output to the DS’s mixer), DS games aren’t able to use it.

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