Tandy SPU

Hardware theme

Uses one of on board sound systems unique to the Tandy 1000 series (IBM-PCjr compatible). Or PCjr sound.


Alternate name: Tandy 3-voice

The first video game about Tandy SPU was released in 1982.

Sierra On-Line, Electronic Arts and Accolade has published most of these games

Often called "Tandy 3-voice", this is not entirely accurate. There was a 4th voice, a noise channel. And Tandy sound integrated the PC Speaker that could be used as a 5th voice (square wave). This arrangement is virtually unique to Tandy 1000 machines and some Tandy specific games used 5 voices. These game will probably be missing the '5th voice' (speaker noise) if played on other hardware and the "Tandy Sound" or "Tandy 3-voice" option is selected.

Voice 1, Square wave, Independent Volume, ABSR can be simulated using the CPU
Voice 2, Square wave, Independent Volume, ABSR can be simulated using the CPU
Voice 3, Square wave, Independent Volume, ABSR can be simulated using the CPU
Voice 4, Noise, Full Volume
Speaker, Square wave, Full Volume only

This is not the same as the IBM PCjr's sound system that could use the PC Speaker OR 3-voice and hardware disallowed using them simultaneously. This xor option was not enforced in the base hardware of other IBMs and compatibles but it was often hardware enforced by add-on sound cards that had a PC Speaker pass-through. A sound card with a PC Speaker pass-through that would play speaker simultaneously with other sound modes was really the only good option since sound from the internal speaker and external add-on speakers simultaneously would be quite dissonant; but not all cards will simultaneously mix with the speaker. So, software also rarely tried to use the speaker with other modes.

Parent group

Sound Processing Units

Related groups

Tandy Graphics Adapter, Tandy 1000 platform, Tandy DAC

compare with these groups


MS-DOS 395

By year

82848688909294969800020406081012141618 1002550750

Popular tags

3.5disk 5.25disk cdrom clickadventure cpu-286 cpu-8086 cpu-8088 display-cga display-cga-composite display-ega display-hgc display-mcga display-tga display-vga dos2 dos3 joystick keyboard mouse sci-engine scummvm spu-adlib spu-adlibgold spu-csm spu-dss spu-gameblaster spu-mt32 spu-pas spu-pcspeaker spu-ps1 spu-sb spu-sbpro spu-tandydac