The improbable music of the ZX Spectrum's one-bit speaker

Even for 1982, the Sinclair ZX Spectrum had poor sound: a piezoelectric speaker that could beep. But you can do a lot with a single bit if you turn it on and off really fast. Michael Martin's Bumbershoot Software site has done some fascinating deep dives into several long-gone computer systems, including a whole series on implementing a game on the ZX Spectrum, starting in May with Giving the ZX Spectrum a Fair Shake. More recently, though, Martin turned his attention to the Spectrum's very limited sound capabilities. As we write, his newest post is Experimenting With 1-Bit Sound. The post concerns the original 16K and 48K ZX Spectrum models, not the Spectrum 128, with its fancy AY-3-8912 sound chip (also found in the US Timex Sinclair 2068). Even as devoted Spectrum enthusiasts, we didn't expect an article about the machine's limited sound hardware to lead to hours of listening pleasure. The Manic Miner intro music, after all, is a fair representation of early Spectrum chiptunes. (Turn your speakers way down before you listen!) The ZX Spectrum could play music from the outset – Steven Vickers' original Spectrum BASIC Manual includes the code for a tiny fragment of Mahler. As The Register reported in 2015, Matt Westcott's Mahler Project used a networked collection of original Spectrum computers to play all the parts of Mahler's First Symphony. Over at Bumbershoot Software, Martin is interested in programming the very limited hardware of these early home computers, and so his Spectrum audio post discusses audio-encoding methods, pulse-width modulation, and more in considerable depth. Toward the end, it links to a remarkable music demo called We are Vocoders. A discussion among Spectrum aficionados on Hacker News then led us to the astounding work of Tim Follin in the 1980s. (The Video Game Music Preservation Foundation has an excellent profile, including a contemporary photo. Dean Belfield's touching tribute to his brother Geoff has a more recent picture.) Follin hand-coded the music for Spectrum games such as Mastertronic's Agent X… And indeed Agent X II… And Raw Recruit… There are many more remarkable Follin tracks, including the music for Future Games, and the title music for Chronos. Follin achieved this without additional hardware such as the RAM Music Machine – which even impressed the great Aphex Twin. There are also some very impressive demos, such as Dark Fusion by the late Ben Daglish. Rich "Tufty" Hollins even created an entire half-hour album of one-bit audio, ON and OFF. You can listen to it in its entirety on Bandcamp, or accompanied by some Spec-tastic graphics on YouTube. ®