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Feature request: Add CQM emulation option. Not a silly request. #28

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zaphod77 opened this issue Jun 28, 2023 · 11 comments
Open

Feature request: Add CQM emulation option. Not a silly request. #28

zaphod77 opened this issue Jun 28, 2023 · 11 comments

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@zaphod77
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Yes, i know CQM is inaccurate, but in at least one case, i strongly believe it's what a game was actually composed for.

I submit the following tune.

https://www.youtube.com/watch?v=KZVHOFijsgE

not too shabby, right?

now listen to it on an actual OPL2.

https://www.youtube.com/watch?v=L2ozNG9_7lU

very thin intro sound. horrible balance, and some notes an octave different (shades of Supaplex)

While it is known that CQM gets Supaplex wrong (because we have the amiga original tune to compare with) comparison with the jaguar original tune seems to suggest that the CQM card plays the tune closer to the original.

Because of this i wish to have the option for an emulated cqm card, for those games where the composer had a cqm card too.

@pachuco
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pachuco commented Jul 31, 2023

I for one want Ensoniq-FM.

https://www.youtube.com/watch?v=NOyax_tLGgs

Very unique sounding.

@Kagamiin
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Kagamiin commented Sep 6, 2023

I do believe CQM emulation is an interesting thing to pursue, as well as emulation of other OPL3 clones found in a variety of other sound cards. However, I don't think that feature should be implemented in Nuked OPL3 itself, since that's not the aim of the project. Nuked OPL3 aims to be an accurate emulator of the OPL3 (and the OPL3-L), not its clones.

That said, Nuked OPL3 is free software, and the codebase can be a great starting point for the development of an emulator aimed at emulating OPL3 clones, an idea that I wholeheartedly support.

Also, I should give my opinion about what OP stated about the example song given from Tempest 2000: I don't believe the Tempest 2000 OST was composed for the Creative CQM card. The first Sound Blaster ViBRA16C with CQM was released in 1995, while Tempest 2000 for MS-DOS was released in 1996. While it's possible that the composer could have been using a sparkling brand new computer with a ViBRA16C, it's unlikely, because Imagitec had been working with MS-DOS soundtracks for so long - it's much more likely that they would have been using their existing Sound Blaster hardware rather than buying a new Sound Blaster card that supposedly did the same job their existing ones had already been doing.

@zaphod77
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zaphod77 commented Sep 6, 2023 via email

@zaphod77
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also check the title tune at the end of the opl2 soundtrack. again we have something that's an octave too low compared to the jaguar original, and i'm 99.9% sure it will be the correct octave on a CQM card.

I literally cannot get this audio from my younger years back while playing the game, because all the existing emulators do actual OPL2 and not the CQM chip.

@pachuco
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pachuco commented Nov 21, 2023

If you really love the CQM, you should make new github project, try and gather some stuff for CQM and friends.

  • how many chips out there discrete(CT1978, CT1978-BAP, CT1978-TAP) or integrated(CT2505, etc.)
  • datasheets.
  • decapsulation images of discrete or integrated chip(I don't think there are any as of yet).
  • patents on CQM(Creative Quadrature Modulation) from Creative or E-mu. This might be most useful step.

But yeah, new github project.

@Kagamiin
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Kagamiin commented Nov 21, 2023

@zaphod77 The most important thing is to figure out what exactly makes CQM sound different from OPL3. In the case of ESFM, for example, we were able to figure out the sound differences for emulation mode using ESS's patents.

I really suggest setting up a research group and gathering as much information as you can. A lot of research and experimentation will be required. You can count me in on this group - I do currently own a Sound Blaster Vibra16 card with CQM, in fact, along with a computer to run it (though I still need to get it up and running).

@zaphod77
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zaphod77 commented Nov 21, 2023 via email

@zaphod77
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okay i think i found the patent here. https://patents.justia.com/patent/6091269

it's the one that talks about OPL3, and how it does things differently, so it should be quite useful.

@Kagamiin
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@zaphod77 it seems to describe a method for generating the sine wave approximation that gives CQM its name, hence the "quadratic" in CQM. It seems important. I'd say try forking Nuked OPL3 and implementing it and see how close to CQM the result is for a starter.

Also, start up a research group. Seriously. You can count me on this.

@zaphod77
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zaphod77 commented Nov 22, 2023

i'll fully admit that's beyond me, but figured throwing info out there would help. :)

i fully expect that except for the octave thing, the notes will sound like they do in tempest 2000 by using these methods of approximation. If the octave ends up changing for those patches as well, i will be very pleasantly surprised.

@zaphod77
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has anyone actually tried this? as i said i have no idea.

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