If you take a listen to System Beeps, you’ll probably be reminded of retro video game soundtracks and modern 8-bit chiptune music. The sound is all square waves and nostalgia. But, unlike most chiptune music, this was created without the help of console sound chips. Instead, it was made entirely in MS-DOS to be played through a motherboard’s built-in speaker. Those speakers were really only ever intended for system beeps — hence the album’s name — which made this quite the undertaking.
As you might recall, you couldn’t just download an MP3 to your computer in the ’80s, which means shiru8bit had to actually write the MS-DOS program that makes up the System Beeps “album.” The hardware is only capable of producing monophonic sound, so just a single voice at a time. To replicate polyphonic sound, they used the CPU to control the 8253 programmable interval timer that actually drives the piezoelectric buzzer. With that method, individual notes can be created and alternated very quickly to give the illusion of polyphonic sound. Not only is it fascinating from a technological perspective, but the System Beeps album is pretty darn catchy too.