DMX (Driver)
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DMX is a sound driver developed by Paul Radek originally to power audio in Cygnus Studios games The Second Sword and Raptor: Call of the Shadows. Soon after id Software licensed it to use in Doom engine. The driver was developed in Watcom C and Turbo Assembler.
Radek created two proprietary audio formats to work with his driver MUS for music and DMX for sound effects and speech. Music must be converted from MIDI files into the MUS format, which is very similar in structure to MIDI. The DMX format supports three different sound effect formats, PCM digital sound effects converted from WAV files, GSS sound effects, and PC speaker sound effects. The digital sound effect structure is similar to WAV and the driver is capable of mixing multiple digital sound effects in real time to allow multiple sound effects to be heard concurrently.
Two of the developers of Doom, John Romero and John Carmack, were displeased with the quality of the driver, and expressed regrets for using it. In particular, some of the versions of the driver had problems with high IRQs, the Gravis UltraSound support was broken in one version, and the later MIDI-to-MUS converter was very limited.
Contents
Release History
The earliest version of the driver was used in the Doom press release beta, though sound and music were disabled. A slightly updated version was released with Doom on December 10th, 1993. This version could support MIDI and AdLib music, GSS and PC Speaker sound effects, digital sound effects sampled at 11,025 Hz, and real-time mixing. A further updated engine was released with the Doom 1.4 patch on June 28, 1994. This added support for the Sound Blaster AWE 32, sound effects sampled up to 22,050 Hz, and and up to 8 sounds mixed in real-time. Another version was released around August 3rd, 1994 which included a built-in MIDI-to-MUS converter so developers could use their own MIDI files.
Output
Music was rendered as FM Synthesis or General MIDI, sound effects could be rendered on the PC Speaker, FM Synthesis, or General MIDI, and speech (and digital sound effects) were rendered on the DAC of the supported sound cards.
| Device | Music | Sound | Speech | Date Supported |
|---|---|---|---|---|
 |
Y | Y | N | 1993-12-10 |
 |
Y | Y | N | 1993-12-10 |
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N | Y | N | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | Y | Y | 1994-06-28 |
 |
Y | Y | N | 1993-12-10 |
 |
Y | Y | Y | 1993-12-10 |
 |
Y | N | Y | 1993-12-10 |
Games
| Released | Title | Sample |
|---|---|---|
| 1993-12-10 | Doom (DOS) | |
| 1994-04-01 | Raptor: Call of the Shadows (DOS) | |
| 1994-10-10 | Doom II: Hell On Earth (DOS) | |
| 1994-12-23 | Heretic (DOS) | |
| 1995-10-30 | Hexen: Beyond Heretic (DOS) | |
| 1996-05-15 | Strife (DOS) | |
| 1996-??-?? | Final Doom (DOS) | |
| 1996-??-?? | Chex Quest (DOS) | |
| 1996-??-?? | Chex Quest 2 (DOS) | |
Links
- doomwiki.org/wiki/DMX - The Doom Wiki.
- aminet.net/package/util/libs/dmxemul - Software emulator of DMX.
