OPL4 - Should I use it in the next game?

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Par Bengalack

Paladin (711)

Portrait de Bengalack

16-10-2022, 13:30

Gist: I'm new to OPL4 and would be super happy if someone could give some quick answers to (some of) these questions.

Listening to some OPL4-material makes you want to use this chip your projects. A nice thought could also be: As more software get written for the chip, the more widespread it would gain.

So:

1: Who has OPL4? Did any vendors release their sales numbers? Does anyone have any idea of the installbase?

2: And does the emulators emulate it FULLY? WebMSX states "OPL4 Wave", does that mean OPL4 fully or just a subset?

3: https://www.msx.org/wiki/Music_replayer_routines lists up two different Moonblaster for Moonsound. One FM and one "Wave" --does that mean that one cannot mix the usage of FM-channels and Wave at the same time? Must use either or?

4: https://www.msx.org/wiki/OPL4 lists up these cards: Wozblaster, Tecnobytes OPL4 Shockwave 1/2, Monster Sound FM Blaster, DalSoRi 1/R2.0, MSX-Blaster OPL4, MSX Calamar Wozblaster Enhanced. Now I read that GR8NET also has OPL4 support. Any others that should be mentioned?

5: The same page states: "Specifications: support for 2MB of Sample-RAM for own samples", but from what I can see most have at least 1MB (I don't know if this is sufficient for a composer these days?). AFAIK, that page does not tell the whole story. Isn't it so that Sunrise Moonsound originally came with 128k? Which could be upgraded to 512, and with some configs of 128+512=640kB? Not sure if the installment ratio between the different OPL4s, but what config to chose as "lowest common denominator" LCD? It is not tempting to set Sunrise as LCD...

6: Do I have to use OPL4-rom BIOS to operate it, or can I use ports directly as we easily can in YM2413 (like as shown here: https://www.msx.org/wiki/MSX-MUSIC_programming)

7: I read somewhere that Moonsound was hooked to the interrupt (as a callback-thingy?). Is it a must to let OPL4 use unknown amount / arbitrary cpu-cycles every frame in your game on an interrupt, or can you play music and operate this chip nicely without this?

8: What tools can composers use to take the FULL ADVANTAGE of this chip? I find https://www.teambomba.net/mbwave.html and http://www.tni.nl/products/ms2.html but any others? Coming in furnace (https://github.com/tildearrow/furnace) or deflemask (https://www.deflemask.com/)?

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Par SjaaQ

Champion (370)

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16-10-2022, 14:11

1) No idea how many are out there. I suppose most of the active MSX users has one.

2) As far as I have tested, only OpenMSX supports it fully. It is also the only emulator in active development. WebMSX can emulate the OPL4 reasonable, but it has a lot of timing issues. It also does not emulate LFO's for example. BlueMSX does not support the timers correctly if I remember correctly, so I've stop using that emulator years ago (it is basically abandonware).

3) Wave is "only" 24 channels of PCM (both from RAM and ROM). FM is 6 channels of PCM, and the (18?) channels of FM. PCM in the FM version is mostly used for percussion and custom samples.

4) Not sure why this matters. The GR8NET is the only OPL4 implementation in FPGA, which is done perfectly. It can only do 512KB RAM with the current cartridges. The GR8NET is also "in active development" so any issues can still be resolved. As far as I know this is the only still available OPL4 compatible cartridge, not taking the current Russia situation in consideration.

5) I have defined the LCD as 512K, also because of the GR8NET limit. The moonsound v1 cannnot be easily exanded, since the chip is soldered. The v2 is pretty easy to expand to max 1MB. Not sure of any of the more recent cartridges. I currently own the Moonsound v1, v2, MSX Blaster and GR8NET.

6) There is no bios in the cartridge. You should directly use the i/o ports.

7) You have two timers which generate interrupts. You mostly use them the same way you use the vblank for timing on the FM-Pac. Biggest advantage is that the music timing will be indifferent to the VDP settings (50/60Hz). You do not need to use these timers at all, if you don't use them, there are no interrupts. Disadvantage of the timers is that they can occur anytime, not only in the border. There is no interrupt to indicate "end of sample" and other fancy stuff. Just two timers.

8) You probably already have all of them. Except a mod player. In SD we just use MODs up to 16 channels. So the tool is actually any program that can create MOD files.

Par Metalion

Paragon (1616)

Portrait de Metalion

16-10-2022, 14:18

The problem with using OPL4 is the number of cartridge slots you need on a real machine. I'm also considering doing a game with OPL4 and with V9990. But most users won't be able to run it (unless they have a slot expander) because they need 3 slots : 1 for the ROM, 1 for the v9990 and 1 for the OPL4.

Par tfh

Prophet (3277)

Portrait de tfh

16-10-2022, 14:42

Well, as long as you also support other sounds chips like for example MSX-Music it can only be considered as a nice plus to do so, so... just go ahead Smile

Par Bengalack

Paladin (711)

Portrait de Bengalack

16-10-2022, 16:09

Totally awesome clarification SjaaQ!

SjaaQ wrote:

4) Not sure why this matters.

It's just that personally I currently do not possess this chip and is wondering which one to get.

tfh wrote:

Well, as long as you also support other sounds chips like for example MSX-Music it can only be considered as a nice plus to do so, so... just go ahead

That would be awesome, but that makes it way more costly and/or complex (compared to only one chip support) as far as I understand. So... yes it makes sense to know how many that are sold / are in use to see if it is worthwhile going for OPL4.

Par Bengalack

Paladin (711)

Portrait de Bengalack

16-10-2022, 16:11

Metalion wrote:

The problem with using OPL4 is the number of cartridge slots you need on a real machine. I'm also considering doing a game with OPL4 and with V9990. But most users won't be able to run it (unless they have a slot expander) because they need 3 slots : 1 for the ROM, 1 for the v9990 and 1 for the OPL4.

Totally see that!!! But there are quite some combo-carts out there, so why not a new v9990+OPL4? It would be a great one.

Par tfh

Prophet (3277)

Portrait de tfh

16-10-2022, 16:30

Bengalack wrote:
tfh wrote:

Well, as long as you also support other sounds chips like for example MSX-Music it can only be considered as a nice plus to do so, so... just go ahead

That would be awesome, but that makes it way more costly and/or complex (compared to only one chip support) as far as I understand. So... yes it makes sense to know how many that are sold / are in use to see if it is worthwhile going for OPL4.

Well, I don't have an OPL4 and don't intend on buying one. I also know quite some people that don't have one. Unless there is a need to only support OPL4 (like Sales Discontinued), I'd suggest supporting other soundchips as well (even if it's only PSG) or not supporting OPL4 at all.

Par tfh

Prophet (3277)

Portrait de tfh

16-10-2022, 16:30

Double post... Sorry!

Par aoineko

Paladin (804)

Portrait de aoineko

16-10-2022, 17:07

SjaaQ wrote:

1) No idea how many are out there. I suppose most of the active MSX users has one.

From talking to MSXVillage users about Sales Discontinued, it appears that very few of the active users had an OPL4 card.
I am one of those who do not have one.

Personally, I wish that games that use OPL4 cards would also have support for PSG, like the early PC games that always offered a beeper version in addition to the support of some sound cards.

Par Jorito

Mr. Ambassadors (1784)

Portrait de Jorito

16-10-2022, 18:19

From a composer perspective that might be completely different though. IMO OPL4 is more interesting to make music for, simply because you have a lot more possibilities (more channels, custom samples, stereo). Sadly there’s not a lot of trackers/programs that allow you to use it to its full potential (at least Moonblaster FM/Wave, they’re very limited even though they at least have drivers to use it in games).

Also, from a musician perspective I don’t really care that some people say it’s not part of the MSX standard Wink
As a musical tool, it gives me more options to make suitable music, rather than hearing the same psg or fm sounds all over again.

Downside of supporting multiple soundchips is that the music has to be made twice, for every soundchip. Apart from the extra work, it also means stuff gets lost and compromised because you can’t really lean in into a single soundchip and get the most out of it. For Bombaman, the FM music was essentially lazy stripped down conversions of the Moonsound music and I hated wasting my time on that.

YMMV, just wanted to share a perspective from the musical side of things.

Par tfh

Prophet (3277)

Portrait de tfh

16-10-2022, 18:35

Jorito wrote:

Also, from a musician perspective I don’t really care that some people say it’s not part of the MSX standard Wink
As a musical tool, it gives me more options to make suitable music, rather than hearing the same psg or fm sounds all over again. .

Then why limit yourself to an 8-bit powersupply and not just go and write software on a PC?

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