DOS Days

Covox / Disney

The Covox Speech Thing receives an 8-bit mono signal via the PC's parallel port, and produces an analogue output than can then be amplified and played through speakers. The sampling rate is not determined by the hardware (the PC software is responsible for sending bytes to the DAC at a given rate to allow for convincing digitised sound) so in theory Covox can support any sampling rate - only the speed of the parallel port limits this however to not even break the CD-quality 44100 kHz barrier. Also, given the fact that the PC was responsible for all the heavy lifting, performance can suffer.

The Covox card doesn't emulate any other formats, such as Ad Lib, Sound Blaster, etc. In a few games that support Disney Sound Source, your Covox can be detected as a Disney Sound Source so you can output sound to your Covox Speech Thing by selecting the 'Disney Sound Source' option. There are some key differences between the two though (more info further down).

If you have a sound card that supports Covox, for example, the Aztech 1st-generation cards, it's likely you need to disable your parallel port or move its address to something other than 378h for Covox emulation to work.


Covox Speech Thing

Price: £84.99 (Nov 1992)

This was an external device that plugged into your PC's parallel port. It sold for $70 USD.

It was a very basic 8-bit DAC (Digital-to-Analogue Converter) which used a resistor ladder and an analogue signal output. It was bundled with speech synthesis software.

"This is one of the oldest sound add-ons available, and it shows. The Speech Thing is one of the devices that plugs into a parallel port, rather than taking up a spare expansion slot. Essentially it is little more than a digital to analogue converter, whihch means that the software has to do all the work as far as generating the sound is concerned.

As its name implies, the Speech Thing has been primarily designed to reproduce speech, but can generate any sampled sounds."
     PC Review, November 1992


Approximately 60 DOS games titles directly support the Covox Speech Thing.

A modern-day clone has been developed called CVX. At the time of writing, it is in its fourth iteration, so is called CVX4. You can purchase this from Serda Shop for 22 EUR.



Disney Sound Source

Price: £35.99 (Nov 1992)

Included here because the Disney card is largely similar to the Covox Speech Thing, and is superior technically. Selecting 'Covox' in a game that supports it should work just fine with your DSS.
It doesn't emulate any other formats, such as Ad Lib, Sound Blaster, etc.

Based on the Covox Speech Thing, this consisted of the same type of DAC but with an added amplifier with low-pass filter/speaker box.

"This newcomer looks like a modern version of the Speech Thing. It connects to the printer port in the same way (and once again, the printer can be connected behind it in a precarious fashion). It also comes supplied with a smarter-looking speaker and volume control, only this one can only be powered by battery.

The Sound Source doesn't come with any set-up or demonstration software, and is principally intended to work with Disney's own software.
"     PC Review, November 1992


Interestingly, despite the fact that the Disney Sound Source is similar to the Covox Speech Thing, Wolfenstein 3D only works with the Disney Sound Source - it does not work with the Covox Speech Thing, Voice Master, or Sound Master. This is explained thanks to one of my contributors, Stefan Goehler. He writes:

"It's not really compatible to Covox, it's just the same principle - meaning to send samples to the parallel port. But it works

1. It only switches on when the software tells it to (there's no physical switch)
2. It can ONLY do 7 kHz
3. It doesn't need such extreme timing as a classic Covox, as it has its own 16-sample FIFO buffer.

So that explains why Wolfenstein won't work with a DSS - it can't detect nor enable the DSS. That's also why no Covox-designed game will play audio on it (no SW-enabling of the thing), also DSS-designed games that just ignore the state of the DSS may not work as well, as they may have been designed to work with the FIFO in mind and don't generate an interrupt every sample, but push a few samples at a given time - to fill the playback buffer again. As the timing would be off in such a case, such games, if they were designed for the DSS, will sound poorly on the Covox."
     Stefan Goehler, May 2023

Stefan also provided a link to his page that covers both the Covox and DSS.

There were almost 150 DOS game titles that directly supported the Disney Sound Source. The following titles directly support Disney Sound Source's digital sound playback without supporting Sound Blaster:

  • Arachnophobia
  • Dick Tracy: The Crime-Solving Adventure

Disney Sound Source Programmers Guide

Covox Voice Master

This is assumed to be the circuitry from the external Voice Master box on an ISA card.



Covox Sound Master (1989)

A very rare card. Uses a Yamaha AY8930 (backward-compatible with the AY-3-8910). Some have the AY8910 instead.

The following titles directly supported the AY8930 PSG, either with music and/or sfx:

  • Conan - The Cimmerian
  • Galleons of Glory
  • Megatraveller 2
  • Prince of Persia (v1.0 only)
  • Punisher, The
  • Sim Earth
  • Spirit of Excalibur
  • Twilight 2000
  • Ultima VI
  • Vengeance of Excalibur
  • Where in Time is Carmen Sandiego (AY8930 music)
  • Where in the World is Carmen Sandiego (320x200 VGA Version)

Several clones of the Sound Master exist that simply connect to your computer's parallel port:

  • Logitech Audioman
  • StreetSound External
  • MediaVision AudioPort
  • DigiSpeech Port*Able Sound Plus
"Laptop users will no longer be left out in the cold when it comes to Windows sound. Logitech's innovative AudioMan, a clever audio board substitute, is an all-in-one, battery-powered external device that plugs into a parallel port.

This product incorporates a unidirectional microphone and a 2-inch speaker into a compact unit not much larger than a mouse. There's also a volume control, a recording indicator light, and an output jack so you can connect AudioMan to an external amplifier or headphones. A separate input jack lets you record from another source, such as a CD player. An optional AC power adapter is also available.

Installation takes about 3 minutes. Simply plug the device into a parallel port and run the install program from Windows. A pass-through connector lets you continue to use your printer from the same parallel port.

When you restart Windows, a new device driver will take effect that provides you with the ability to make 8-bit mono recordings sampled at 11 kHz. The unit also lets you play back WAV format sound files - a common file format used in many multimedia applications. Unlike a sound board, AudioMan doesn't have a synthesizer, so you can't play MIDI files.

Probably the most common application for AudioMan will be voice annotation using the Windows OLE Sound server application. Not all Windows applications support OLE, but the list is growing fast.

AudioMan will be available in late December at a list price of $179."
     InfoWorld, November 1992


Covox Sound Master + (1992)

Introduced: 1992
Bus Interface: 8-bit ISA
Price: £79.99 (Nov 1992)

A card that supports Speech Thing and Ad Lib audio.

"Having recognised perhaps, that its Speech Thing was getting a little long in the tooth, and the most PC games players demand more sophisticated sound output, Covox has come up with the Soundmaster+. Unlike the Speech Thing, this is a card, although full marks to Covox for making it the most compact of those I've reviewed. It only requires an 8-bit slot and should be small enough to fit into many compact machines, as well as standard size desktops.
Like the Sound Blaster and Sound Galaxy [NX], Soundmaster+ supports two modes of sound generation, digitised sound and tone generation. Both of these modes emulate another sound device. Tone generation is compatible with the basic Ad Lib board. The digitised sound mode, however, emulates the Speech Thing. Covox claims that to emulate the Sound Blasters digitised output would have have a technological step backwards. That may well be, but in Europe at least, support for the Sound Blaster is far greater than it is for the Speech Thing."
     PC Review, November 1992


Covox Sound Master 2 (1992)

Introduced: 1992
Bus Interface: 8-bit ISA
Price: £79.99 (Nov 1992)

"The most expensive board in the Covox range is potentially one of the most exciting of the devices in its price range, but is let down by a couple of minor points. While it is essentially based on the Soundmaster+, including the Speech Thing and Ad Lib support, it boasts some impressive additional features.
Like the Sound Blaster and Sound Galaxy [NX], Sound Master II has a microphone input so that you can sample your own sounds, but it also has an alternative function. Soundmaster II emulates the Voice Recognition functions of the Covox Voice Master. This enables you to add voice commands to existing software, but, be warned, it takes some patience to get it set up exactly as you want it and working properly. The Soundmaster II also incorporates a MIDI interface and PC-Lyra music composition software.
The Soundmaster II is sadly lacking joystick support and Sound Blaster emulation. With these two improvements and it's versatility it would have been an ideal first buy or upgrade."
     PC Review, November 1992