Digital Audio on the ZX Spectrum's 1-Bit Beeper | Hacker News Reader

Digital Audio on the ZX Spectrum's 1-Bit Beeper

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66 pointsibobev23 comments

Doing stuff like this in the 8-bit era was never particularly hard. The difficulty was doing this and then anything else, because you basically need the entire CPU just for audio synthesis. For games, there was a very real trade-off between calculating video, game state, and sound, and sound often took the back seat.

It's also why everything looked and sounded better on 8-bit computers that had hardware support for graphic sprites or sound generation, even if they had a less powerful CPU. And it's the untold story behind why 16-bit graphics looked so much better: it wasn't about the CPU as much as it was about having a dedicated video card / chipset with its own memory, a sound card that handled polyphonic sound and MIDI synthesis, etc.

I wrote a Reg article based on this:

https://www.theregister.com/offbeat/2026/09/13/the-improbabl...

I got some valuable links to tunes from a previous HN thread:

https://news.ycombinator.com/item?id=49611230

It was just 3 weeks ago...

I have a memory of a Spectrum game playing some sort of synthesised speech through the speaker that seemed incredibly ahead of its time. I believe the game was called iBall. And the sample said something like “Fight iBall!” Have I misremembered that? Was this a fever dream?

Robocop was another game with sampled speach, not yet mentioned:

https://www.youtube.com/watch?v=Dy8kZcGz98U

There were a few games (in later years) with speach/audio. But Robocop was one that stands in my memory for the good music.

Another Speccy game with digitized speech is Chase HQ:

https://youtu.be/yjrbcLm78I8?si=GMIqDdL31hq4ik72&t=87

Although tbf apparently that's done via the AY sound chip of the 128k, which is a lot easier than through the on/off beeper of the 48k since the AY can do digitized audio via CPU-driven volume modulation.

There was also "Meteor Storm":

https://spectrumgamesuk.com/index.php?game=Meteor-Storm

I think it said "Meteor Alert!" or something similar, though the quality was terrible.

The 128k version of Nodes of Yesod had some speech, albeit I think it was just the name of the game. My older brother told me a kid in his class got paid big bucks - like, I dunno, £50 or something? - for coding it. Almost certainly bollocks.

For high quality speech, you could get the Currah μSpeech! https://en.wikipedia.org/wiki/Currah#Currah_%CE%BCSpeech_for...

I swear there was one symbol it pronounced "flea bleep".

For some reason "5", even if constructed as phonemes came out as "frame" - I always wondered why. I've never seen it mentioned in the various short pieces about it online including its contemporary reviews. I wonder now if it was a bug in the particular rom I had and it was fixed early enough to not get much visibility.

Jonah Barrington's Squash used synthesised speech for scores

I remember the "Codemasters Jet Bike Simulator". I always found it impressive

(And there was a "Get ready!" which I didn't remember)

https://www.youtube.com/watch?v=hRW9vW3_M3o&t=8

I remember "Rocman", how hearing a human voice coming from a 1-bit beeper sounded like sorcery: https://youtu.be/iuT0hxjLCzc?t=95

You might be right! I had a copy of 'Slightly Magic' which had some speech synthesis. Great game. Never completed it though

You remembered correctly!

https://zxart.ee/prod/101558

And who could possibly forget Chronos' title music, by Tim Follin?

https://www.youtube.com/watch?v=u-D24A_N4d4

and AgentX by the same composer.

There was a music editor I remember getting on a late Your Sinclair edition cover tape which displayed proper music staves and gave you 4-note chord output. Blew my mind a bit at the time.

Does the Speccy have enough outputs on the edge connector to make a simple DAC like the parallel port ones we used to make with a bunch of resistors for the PC?

e.g. the homemade versions of this:

https://en.wikipedia.org/wiki/Covox_Speech_Thing

Nice idea, it has 8 data lines, so 8 bits audio should be possible.

Due to all the constraints the ZX Spectrum is a fantastic system for recreational programming; too bad I missed the latest Spectrum Next batch last year.

This reminded me of a recent very detailed video on polyphony implementation on 8052

https://news.ycombinator.com/item?id=49895486

There's also a phone with YM2149

See also what the C64 could achieve, via the demo "Cubase64"

https://www.youtube.com/watch?v=PTGkf21UpJ8

How it works: https://livet.se/mahoney/c64-files/Cubase64_White_Paper_by_P...

ZX's audio and video systems are two things that I never missed.

The computed jump into a NOP sled is a nice trick for getting a fine-grained delay without spending registers on a counter. I'm curious how much contended memory got in the way: on the 48K, code or sample data sitting in the lower 16K gets stalled by the ULA during screen fetch, which seems like it would wreck cycle-exact pulse widths unless everything lives above 0x8000. Did you end up having to place things carefully for that, and did the 128K/+2/+3 contention differences show up in the hardware tests? It's also interesting that the first attempts mostly produced the 8kHz carrier, since that's squarely in the audible range where the PC's 16kHz-ish carrier was easier to ignore.

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