VOGONS


Covox Sound Devices

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First post, by Great Hierophant

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Covox made five important sound devices for the PC before going out of business in the early 90's.

The first was the Covox Speech Thing, a cheap parallel port DAC. It could produce mono 8-bit digitized sound at a rate determined by the system. It also had the ability to connect another parallel device from the picture I have seen.

The second was the Covox Voice Master/Voice Master Jr./Voice Master Key, which was also available for the Apple II in card form and the Atari 8-bit and Commodore 64 computers via an external box that attached to one of the joystick ports. I have read that the Voice Master came both as a parallel port attachment and as an ISA card. This operates on the same principle as the Speech Thing, but has extra hardware to convert speech into text. In addition, the software can do text to speech and rudimentary speech recognition.

The third was the Covox Sound Master, Covox's first attempt to compete with the Adlib. It used an AY8930 chip for music, had two 9-pin digital Atari style joystick ports, and had a DMA driven DAC. While the I/O ports of this device are known, the number of Interrupts and DMA channels, including which, are not.

The fourth was the Covox Sound Master Plus, a sort of a stopgap between the last and the next card. From the little information I have gathered, the AY8930 chip seems to have been replaced with the YM3812 chip of the Adlib. I don't know anything else about this card.

The fifth and final card from Covox was the Covox Sound Master II. This 8-bit ISA card claimed to be Adlib & Sound Blaster compatible, but Sound Blaster compatibility had to be obtained with a TSR. This card definitely had a YM3812 and an regular analog gameport. As usual, the gameport doubled as a midi port. It had an 8-bit mono DAC, which used one interrupt while the midi port required another. Its I/O ports are the same as the original Sound Master's, not a copy of any Sound Blaster. It advertised Speech Thing compatibility without additional drivers. It also used a DMA channel for digital sound, and was better known for its speech-recognition.

Reply 1 of 26, by eL_PuSHeR

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I had a Covox Soundmaster+ in my 8086. I think it had the same midi chip Adlib had. 100% Adlib compatibility but too little games using the analog DAC, Alone in the dark to name one.

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Reply 3 of 26, by Great Hierophant

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Which of these babies except Speech Thing designed for external connection to LPT too?

By all reports most of the Voice Master products could be connected to the parallel port interface. The Sound Master II is an ISA card but works with Speech Thing software without drivers, which implies that it has a parallel port interface on the card. However, the Sound Master II has no jumpers to select the appropriate parallel port addresses, which means it must be stuck at 378h.

Reply 4 of 26, by Great Hierophant

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Further information from Covox:

There were two products available for the PC in the Voice Master line, at least as of August 1991:

First, the Voice Master Key, an 8-bit ISA card with D/A and A/D converters. It could do programmed I/O and DMA I/O.

Second, the Voice Master Key II, an external box that hooks up to the parallel port. It is not advertised as being capable of DMA I/O, but that is probably more a limitation of the parallel ports in existence at the time (ECP mode, which utilized DMA, not being defined until 1992.)

The Sound Master II contains identical digitized recording and playback hardware as the Voice Master. As it was available as of August 1991, this implies that the earlier Sound Master products had a much briefer lifespan (maybe two years.) If the original Sound Master uses the same hardware, then we have come a way to figuring out how it works.

Reply 5 of 26, by QBiN

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I've still got my Covox Speech Thing. I have only one game that uses it: 688 Attack Sub.

yeah... it's... erm... quaint. 😀 But a nice collector's piece.

Reply 6 of 26, by ih8registrations

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I've only seen a speech thing for auction once on ebay, but for quite awhile disney sound sources were readily available. There's actually an auction right now for a specialty item by covox for the hearing impaired, the only other covox hardware I've seen auctioned.

Last edited by ih8registrations on 2006-11-09, 05:22. Edited 1 time in total.

Reply 7 of 26, by Great Hierophant

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That is the Voice Master Key II, not particularly interesting for gaming purposes (although Wizardry VII can use it for digitized sound.)

Wizardry VI: Bane of the Cosmic Forge - Does not have any music, so while it supports the Covox Sound Master, it only does so for its DAC. It also supports the Sound Blaster as well, so no loss there.

Wizardry VII: Crusaders of the Dark Savant - Supports Covox Sound Master, Covox Voice Master & Covox Sound Master II for sound effects, but only supports Covox Sound Master II for music. Again no loss there because it also supports the Adlib, Sound Blaster and Roland LAPC-I as well for music.

Reply 8 of 26, by Great Hierophant

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Apparently, Covox had first implemented the original Sound Master for the Apple IIs in 1984. The AY8930 chip is downards compatible with the AY-3-8910 chips used by the Mockingboard sound cards, so presumably it was advertised as being "Mockingboard Compatible."

In summary, based on the evidence I think there were four major types of digital audio capabilities for the Covox line:

Type I - Found in the Covox Speech Thing and in the Covox Voice Master Key II. This is an external, parallel port DAC, and can only use the programmed I/O method.

Type II - Found in the Covox Voice Master Key II. This parallel port device uses a DAC like the Speech Thing but adds an ADC for recording voice samples, but is still limited to the programmed I/O method.

Type III - Found in the Covox Soundmaster and Covox Soundmaster+. These ISA cards are compatible with Speech Thing software and can utilize the programmed I/O and DMA methods.

Type IV - Found in the Covox Soundmaster II and Covox Voice Master Key. These ISA cards add a ADC as well as a DAC for recording and playback. Can utilize the programmed I/O and DMA methods.

Also, the Soundmaster+ has midi capabilities like the Soundmaster II, so it must have a 15-pin analog gameport. The only real difference between it and the Soundmaster II is the added recording hardware of the Voice Master Key.

Reply 9 of 26, by Malik

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(Malik has become a Necromancer - last post was in 2006!! Back when the thread was somewhere else, because there was no Milliways or Marvin back then! 🤣)

But the thread title is informative and knowledge based.

Regarding the Sound Master II :

How's the MPU-401 compatibility using the MIDI/Gameport port? I suspect it only used the UART mode. I had one and sold it. I never used the MIDI port to check it though.

P.S. And if there's interest in this thread, can we move it to Marvin or Milliways?

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Reply 10 of 26, by Great Hierophant

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The problem with Covox products is that they are poorly documented, especially at the hardware level. This thread has some inaccurate information based on the knowledge available at the time. The Sound Master Plus, for example, is little more than an Adlib with a very basic DAC. The Sound Master II didn't have a gameport, it's MIDI interface was a 9-pin dongle.

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Reply 12 of 26, by Great Hierophant

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The Covox Speech Thing resides at the LPT addresses, 378, 278 or 3BC (if an MDA is present). There was an external version of the Voice Master which could do that and allow for recording (5-bit?) as well through the parallel port.

The Sound Master Plus and the Sound Master II have Adlib ports at 380 or 388, but the Sound Master Plus has a DAC at 330/338 while the Sound Master II has its MIDI ports at 330/338. So much for compatibility across the line.

The Sound Master and the Sound Master II can use 22x, 24x, 28x, & 2Cx for its DAC/ADC, DMA 1 or 3 and IRQ 2, 3, 5, 7 for the DAC/ADC and IRQ 2, 3, 5, 7 for MIDI. Its MIDI cable uses a DB-9 connector on one end and two 5-pin DINs on the other end.

I have a photo of a Covox Voice Master with DMA, and one without DMA, the Covox Voice Master VMPCY 1.1. According to the schematic, the DMA-less Voice Master seems to use the same method as a Speech Thing to produce digitized output, but at the 22x, 24x, 28x or 2Cx ports. The DMA-driven Voice Master, VMDMA 1.2 may have been marketed using the name Covox Voice Master II.

All detailed PCBs of the Sound Masters and Voice Masters have a 74HC373 8-bit Latch and a resistor pack which can be used for Speech Thing output. I assume the Sound Master also has one, but I do not have a detailed PCB shot to check. The Sound Master I, Sound Master II and Voice Master II all can use DMA driven DAC, although whether they all do so in the same or a compatible way is unknown. On a parallel port, there is a 74LS374 which does the same thing.

Super Jeopardy supports the Covox Speech Thing and the Covox Voice Master, but the internal Voice Master only. Selecting the Voice Master will make no sound in DOSBox.

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Reply 14 of 26, by retrofanatic

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Thanks for reviving this topic Malik...and great information as always from Great Heirophant...from lurking on Vogons before I joined, I have learned much about sound cards and such from you guys..thanks. I am looking forward to adding a covox sound device to my collection soon.

Reply 15 of 26, by BobNJ

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I have acquired a COVOX Master Key (System II) which connects to a PC via the parallel printer port. This one appears to be different than the photos I've seen in that mine has a 4" speaker mounted on top whereas the photos on the internet show a small speaker mounted on the front panel. Does anyone have any information as to why there are 2 configurations? Which one came first?

I've been trying to test it. So far I've applied power and the two LEDs on the front panel light up and I can hear some background white noise from the speaker. I am looking for COVOX program disk for this device.

So far I've found a copy of the v2.04 disk that was supplied with the bus card version of the Master Key, but what I need is v2.04X which directs the I/O to the LPT port. I've searched the internet but cannot find a copy of that software.

I would appreciate some words of wisdom and advice from you folks. Thanks!

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Reply 16 of 26, by SEGStriker

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There are lot of games supporting Covox Speech Thing (LPT DAC). And there are many that are supporting Disney Sound Source and some of them could be lied by Covoxer or another tool to believe ordinary Covox is DSS. Also, there are other LPT DACs like STON1 - Stereo-on-1 which are more than one DAC on one LPT port. It could be detected by some programs (Mod Player for example) just as DSS, so it is not passive like Covox Speech Thing. I don't know any game that is supporting it though.

Reply 18 of 26, by Neville

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I was looking for info on other Covox products than the Covox Speech Thing and found this article:

http://nerdlypleasures.blogspot.com.es/2014/09/the-mysterious-covox-pc-sound-devices.html

It may contain more helpful information. Personally, I'd love to see more Covox devices emulated in DOSBox or POCem, but I understand the lack of technical information is an enormous obstacle.

Reply 19 of 26, by matze79

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All detailed PCBs of the Sound Masters and Voice Masters have a 74HC373 8-bit Latch and a resistor pack which can be used for Speech Thing output. I assume the Sound Master also has one

Making a internal ISA Covox hmm, is it enough to hook up a Latch to LPT Base Adress ?
Or do they use additional parts ?

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