16

Sounds from the Atari 8-bit computer line came through the RF video cable into your television much like video game systems from the time. The original Atari 400/800 also had a built in speaker, though from what I can tell it only produced the keyboard "click" sounds and wasn't meant to do anything else. I don't think the internal speaker was included in the later XL and XE lines.

Was the internal speaker of the original 400/800 usable for anything other than the keyboard click? That being said, how was it hooked up in the architecture? By this I mean was it tied to one of the POKEY channels (doubtful) or was there dedicated circuitry for the speaker?

  • It's similar to the The ZX Spectrum 128K that had the sound channels via the TV and a buzzer in the computer. It was used by Tim Follin in the soundtrack for Chronos and Agent-X 2. – liftarn Oct 26 '16 at 12:16
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The speaker was known as the console speaker and is controlled using the byte at location 53279; as indicated in Mapping the Atari:

POKEing any number from zero to eight will cause a click from the speaker.

The book also includes a program listing based on a COMPUTE! article, illustrating how to play different tones on the console speaker.

The Atari 400/800 service manual mentions specific circuitry on the motherboard, which

Provides the driving circuitry for the Key-Press signal from the Central Processing Unit PCB to the Console speaker.

(page 1-12). Page 1-18 of the service manual shows the Atari 400 motherboard block diagram; the keyboard speaker is connected to the CPU board via a connector jack (J106), and the circuit doesn't go through POKEY. Page 1-20 shows the same information for the Atari 800, with the same layout but a different number for the connector jack (J105).

The console speaker was removed in later systems; the key click was routed through the TV speaker and could be disabled (see the Atari 8-bit FAQ).

  • I believe the game Ultima III employed the Atari's internal speaker, using it for "combat noises", so that there would be additional POKEY resources for the game music. – Crossfit_and_Beer Feb 8 '18 at 11:58
  • Indeed @Crossfit_and_Beer, the difference between the built-in speaker and the POKEY music is clearly audible in this video! – Stephen Kitt Feb 8 '18 at 15:05

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