Covox Sound Master Reverse Engineering / Replica

Discussion about old sound cards, MIDI devices and sound related accessories.

Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-2-19 @ 19:44

awgamer wrote: As for tandy, I thought many games expect jr/tandy video, sound, and memory mapping to work properly, much more of a pita.


According to Cloudschatze the majority of games from large publishers he tested provided command-line switches for Tandy Sound + EGA/VGA.

What we would need is someone well versed in X86 assembly to try and do the something similar as TEMU does. Redirect the C0h range writes via a TSR to the 3 voice generator. This is necessary because of the location of the second DMA controller.

Jepael actually makes great technical points here.

But all these issues should be on its own thread.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-2-19 @ 19:53

Marmes wrote:If gal is not registred it's possible to read it, even if it's protected .


This guy did it, and did it with a PAL. Problem is these cards are extremely rare. AFAIK, only 2 are known to exist. One is from Yvan who is trying his best to help us, other is some dude from Idaho that Cloudschatze has tried to contact without success. I even contacted Nick Skrepetos who worked for Covox, but so far only thing i got from him is: "Carlos, i am that Nick".
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Fagear » 2015-2-19 @ 23:25

carlostex wrote:This guy did it, and did it with a PAL.

I'm trying to figure out the methodology of this process and then I'll try to automate this in some way.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Marmes » 2015-2-19 @ 23:33

No need for that, all you need is a good programmer that read pals, the rest is easy :), then again if PAL is not registred
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Re: Covox Sound Master Reverse Engineering / Replica

Postby awgamer » 2015-2-20 @ 08:12

carlostex wrote:
awgamer wrote: As for tandy, I thought many games expect jr/tandy video, sound, and memory mapping to work properly, much more of a pita.


According to Cloudschatze the majority of games from large publishers he tested provided command-line switches for Tandy Sound + EGA/VGA.

What we would need is someone well versed in X86 assembly to try and do the something similar as TEMU does. Redirect the C0h range writes via a TSR to the 3 voice generator. This is necessary because of the location of the second DMA controller.

Jepael actually makes great technical points here.

But all these issues should be on its own thread.


You can look at the GUS's SBOS source. The limitation of SBOS being it was for real mode, which shouldn't be a problem for most jr/tandy games.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-15 @ 19:54

carlostex wrote:
Marmes wrote:If gal is not registred it's possible to read it, even if it's protected .


This guy did it, and did it with a PAL. Problem is these cards are extremely rare. AFAIK, only 2 are known to exist. One is from Yvan who is trying his best to help us, other is some dude from Idaho that Cloudschatze has tried to contact without success. I even contacted Nick Skrepetos who worked for Covox, but so far only thing i got from him is: "Carlos, i am that Nick".


Hi, I received a Covox Sound Master today.
I tested it with Prince of Persia: Music and Sound Effects are working. Lucky me.
I don't know how I could help the project to go further. Let me know.

Does anyone of you know what this red wire (with a molex 3-Pin) is good for? I have no clue.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-8-15 @ 20:33

You can certainly help and a lot! You can try to put a light under the card and take pictures at shallow angles, so that our engineer Fagear can figure out the hidden traces under the chips.

There is also a huge contribution you can make. If you are willing to help us out, there's a way where we can get the PAL chip desoldered on your card and send it to a company who can get the logic from it. Keropi managed to do this with his Music Quest MPU card, which also had a protected PAL.

With the PAL code and the hidden traces figured there's only small problems in the way that can be eventually solved.

In the mean time you could post some videos of your card playing whatever games you can remember.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-16 @ 11:54

Here is the first try. Does it help to see the hidden traces?
Unfortunately I do not own a macro objective for my system camera.
You can check out the pics here: http://hierbilder.de/rKoOG
Otherwise give me some instructions.

Regarding the PAL. I'll do my best to help.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-8-18 @ 01:01

Thanks for the pics!!!

I'm not too sure, but at first hand it seems that Fagear already figured out pretty much all that what your pics show. The idea is too put the camera at shallow angles so that the traces under the IC's are revealed. Here is Fagear's post about it:

viewtopic.php?f=46&t=40512&start=80#p402174

In the mean time thank you for helping us out. Deeply appreciated :cool:
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Great Hierophant » 2015-8-18 @ 17:05

moturimi1 wrote:Hi, I received a Covox Sound Master today.
I tested it with Prince of Persia: Music and Sound Effects are working. Lucky me.
I don't know how I could help the project to go further. Let me know.

Does anyone of you know what this red wire (with a molex 3-Pin) is good for? I have no clue.


In the meantime, a recording or two or as many as you would like :cool: from the card would be greatly appreciated.
http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-18 @ 21:32

Great Hierophant wrote:In the meantime, a recording or two or as many as you would like :cool: from the card would be greatly appreciated.


I'll do my best.
I will record the main themes/intro of Prince of Persia and Ultima VI (till the end of the week hopefully).
But I am afraid, that the recordings will be really noisy as I do not want to move my professional equipment to the vintage stuff in the basement.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-8-18 @ 21:45

^And some videos if its easy enough for you. :)
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Re: Covox Sound Master Reverse Engineering / Replica

Postby keropi » 2015-8-18 @ 21:46

I'm really curious to hear how this sounds too, can't wait for the recordings :D
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Fagear » 2015-8-19 @ 14:41

moturimi1 wrote:Does it help to see the hidden traces?

Hi!
Unfortunately, not quite. I've added some more traces after your photos, but I need to see under all ICs. And also around output connectors.
Photos from various shallow angles will be much appreciated.

Current progress:
Image
Added some new traces and ground polygon at analog part.

P.S. I have no time to deal with PAL/GAL restoration procedure.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-8-19 @ 15:08

Traces everywhere. Seriously, awesome work Fagear considering how awful the board layout is.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-20 @ 18:35

Here is a first comparison from music within Ultima 6:
Covox Sound Master: https://www.dropbox.com/s/7x8nulv9sg51r ... x.mp3?dl=0
Ati Stereo F/X CMS: https://www.dropbox.com/s/2tz2gi6eubx39 ... I.mp3?dl=0
Sound Blaster 2.0 CMS: https://www.dropbox.com/s/rxppq8c1hukmw ... 0.mp3?dl=0
Ati Stereo F/X OPL2: https://www.dropbox.com/s/987ppeptbujyn ... i.mp3?dl=0
Sound Blaster 2.0 OPL2: https://www.dropbox.com/s/vi3xf70k25bxy ... 0.mp3?dl=0
Aztech SG NXII OPL3: https://www.dropbox.com/s/gh31ibvyplpva ... b.mp3?dl=0

I normalized the peak volume level.
Ati Stereo F/X add sort of stereo sound effects.
Last edited by moturimi1 on 2016-3-27 @ 11:52, edited 2 times in total.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2015-8-20 @ 20:34

Ahhh, that 3 voice PSG style sound... I really like the way the AY-8930 sounds. This Covox Sound Master will be definitely be worth to replicate. I'm specially interested in hearing the Covox Sound Master on Prince of Persia.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-20 @ 21:00

carlostex wrote:Ahhh, that 3 voice PSG style sound... I really like the way the AY-8930 sounds. This Covox Sound Master will be definitely be worth to replicate. I'm specially interested in hearing the Covox Sound Master on Prince of Persia.


Here is the intro of Prince of Persia:
Covox Sound Master: https://www.dropbox.com/s/nspdzva35c2dv ... x.mp3?dl=0
Aztech SG NXII OPL3: https://www.dropbox.com/s/npu155dwndl49 ... b.mp3?dl=0

...besides "music" you can hear some "sounds" (DAC or DMA?)
Last edited by moturimi1 on 2016-3-27 @ 11:53, edited 1 time in total.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby moturimi1 » 2015-8-20 @ 21:05

Here is more from Ultima 6:
Covox Sound Master: https://www.dropbox.com/s/iti13m5syjejj ... x.mp3?dl=0
Ati Stereo F/X CMS: https://www.dropbox.com/s/cn8buzvjpmtd8 ... i.mp3?dl=0
Sound Blaster 2.0 CMS: https://www.dropbox.com/s/y464qhldzael1 ... 0.mp3?dl=0
Ati Stereo F/X OPL2: https://www.dropbox.com/s/pe67jbgcq9lg5 ... i.mp3?dl=0
Sound Blaster 2.0 OPL2: https://www.dropbox.com/s/bf89ctzi9yge6 ... 0.mp3?dl=0
Aztech SG NXII OPL3: https://www.dropbox.com/s/zb0wwimi6atb6 ... I.mp3?dl=0

Strange artefacts (hiccups) starting after around 25 seconds in case of OPL2 and OPL3 playback. Maybe due to the slow down of the copmuter (turned of L1 and L2 Cache) so that ATI and other 8-Bit cards do not have issues. Or is it related to the OPL2/OPL3 Yamaha sound chip?
Last edited by moturimi1 on 2016-3-27 @ 11:49, edited 1 time in total.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby keropi » 2015-8-20 @ 21:18

thanks for the recordings!
I'll be honest here, I can't say that I particularly like the way soundmaster sounds... I believe it's a case of not enough effort put into it by the devs...
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