Tandy Sound and Wolfenstein 3D? Disney Sound Source?

[Zombie]

I am curious, has anyone managed to make a Tandy 3-Voice function as a Covox Speech thing or Disney Sound Suource? Could it make the Tandy support Sound in Wolf3D on the Tandy 1000 TL?

 

[eeguru]

This seems like an apples v oranges comparison. Tandy 3-voice is from an FM synthesis chip while Covox and derivatives send PCM using a low frequency timer straight out the parallel port to an R2R ladder.

I'm not aware of any limitation preventing a Covox box working on a T1K however - assuming you deal with the funky card edge connector on the 1st gens.

 

[dlightman]

Per Great Hierophant's site Setdac from tspak181.zip (ftp://ftp.oldskool.org/pub/tvdog/tandy1000/sound/tspak181.zip) will use the Tandy DAC to emulate Covox.

Information from here: http://nerdlypleasures.blogspot.com/2014/03/a-hypothesis-of-tandy-1000-parallel.html

The Covox Speech Thing is a simpler device that does not use anything other than the data port, which is connected to a purely-passive resistor network to an audio jack. The Tandy PSSJ DAC can emulate a Covox device using a program called Setdac, assuming the Covox-supporting program obeys DOS LPT address assignments.

 

[Trixter]

The Tandy 3-voice chip can be bit-banged to simulate a 4-bit DAC, however the volume levels are logarithmic instead of linear, so it sounds pretty rough. Unfortunately, the values sent to the 3-voice chip are not in the form of linear 8-bit PCM like you send to a Covox or DSS, so there is no easy way to make it work. (It is technically possible, but requires a 386 or higher so that you can use the V8086 mode of the processor to trap port writes, however there is no point in doing this, since every Tandy ever made with a 386 has the TL/DAC chip, so you can just output audio that way without trouble.)

 

[dJOS]

I'm not aware of any limitation preventing a Covox box working on a T1K however - assuming you deal with the funky card edge connector on the 1st gens.

That part is easy!

Not sure why you'd want to tho ... Although I have been tempted to try my old Covox clone on my EX just for laughs.

 

[Scali]

Perhaps it would be easier to just adapt the source code of Wolf3D?
The Covox needs to be bitbanged on a port. Playing samples on the SN76489 chip works basically the same. Only the samples have to be converted from 8-bit PCM to 4-bit logarithmic. This could probably be done at startup-time.
So I think that building a custom version of Wolf3d for this purpose would be a simple and clean solution.

 

[Timo W.]

Why bother at all? Wolfenstein 3D will not run at playable speed on the TL anyway. Non DMA-assisted PCM playback will not make it any better.

 

[Great Hierophant]

I agree that Wolfenstein 3D running in a stock Tandy 1000TL will be too slow to be enjoyable, if you have an accelerator in the TL, it can get playable. The TL does have a DMA-assisted DAC, but Wolf 3D does not support it. You can use a Sound Blaster Pro for PCM. You can use a Disney Sound Source for PCM, but you need to use a parallel port on an ISA card.

 

[keenerb]

Why bother at all? Wolfenstein 3D will not run at playable speed on the TL anyway. Non DMA-assisted PCM playback will not make it any better.

Some later AT-class Tandy hardware still has the DAC, but at a different address, like my 2500SX/20...

 

[Great Hierophant]

This seems like an apples v oranges comparison. Tandy 3-voice is from an programmable sound generator while PC games send PCM using a frequency timer straight out the parallel port to the Covox and derivatives' R2R ladder which acts as a crude DAC.

I'm not aware of any limitation preventing a Covox box working on a T1K however - assuming you deal with the funky card edge connector on the 1st gens.

Fixed some errors there.