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PostPosted: Sun Dec 10, 2017 2:09 am 
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We started talking a lot about this in the SNES sound hardware discussion, so I thought hell, why not. I was talking about how I thought the Neo Geo's sound hardware was bad, but holly hell, this has got to be the worst sounding arcade board in existence: https://www.youtube.com/watch?v=Iuhx1PyLppQ http://system16.com/hardware.php?id=952 Having sound solely comprised of two OKI6295s is a bad idea. :lol: That arcade board is really an anomaly over all; it's from 1994, You'd dismiss this for being a low-budget POS, but it has a 28MHz ARM processor.

Edit: Video hardware information was false, so I removed it.


Last edited by Espozo on Sun Dec 10, 2017 6:09 pm, edited 1 time in total.

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PostPosted: Sun Dec 10, 2017 10:48 am 
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At first I thought this was just a bad programming job, theb I found documentation for the chips, and they have a sampling rate of either 8khz or 6.5khz, no other pitches are available. Then there's a lowpass filter, but 8khz sounds bad with or without a lowpass filter anyway.


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PostPosted: Sun Dec 10, 2017 11:00 am 
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Probably it was designed by deaf engineers thinking "Who cares about sound anyway ?".


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PostPosted: Sun Dec 10, 2017 11:05 am 
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That and in a noisy arcade, crystal clear audio might not necessarily be heard over the two adjacent games also in use. When your game's cabinet is as physically imposing as a Dance Dance Revolution or other 2-player Bemani game, sparing no expense for audio is justified. But not all games are that big.


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PostPosted: Sun Dec 10, 2017 5:53 pm 
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Who knows what Mitchell were thinking?

Considering that it has limited sample streaming, it sounds pretty good. It could have been much worse in the wrong hands: https://www.youtube.com/watch?v=vZ_Qas_Yl8E

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PostPosted: Sun Dec 10, 2017 7:05 pm 
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ccovell wrote:
https://www.youtube.com/watch?v=vZ_Qas_Yl8E

Is this for real? :lol:

psycopathicteen wrote:
At first I thought this was just a bad programming job

Same here; it sounds too bad to be in hardware. It actually reminds me a lot of a lower quality GBA game. I've know of several arcade machines with the OKI6295, but none of them rely on it solely, usually pairing it with the YM2151 (CPS1). I can't believe how long it lasted though considering how low spec it is (look at the dates of some of these games): http://vgmrips.net/packs/chip/okim6295?

I actually downloaded the rom for the game and looked at it in MAME, and it turns out that this doesn't actually have 3BG layers; it only has two. One of the layers appears to use 8x8 tiles, while the other appears to use 16x16. The status bar is actually just sprites; 8x8 numbers used to represent the score are actually 16x16 sprites, which seems like a huge waste of bandwidth. The game didn't ever actually have sprite dropout of any kind, despite how heavily it relies on sprites. (Several large background elements in the game are even made of sprites) You know Sega would have relegated this hardware to puzzle games only. :lol:

ccovell wrote:
Who knows what Mitchell were thinking?

It appears to be Data East's arcade machine that Mitchell just used. I'd ask what Data East was doing first. It actually appears they had an otherwise identical arcade machine aside from the sound hardware that was released earlier: http://system16.com/hardware.php?id=954 It's still 8 channels, but it sounds clearly better: https://www.youtube.com/watch?v=2QCD8u-3YTw Of course, both companies weren't exactly rich, so they had to work with "substandard" hardware.


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PostPosted: Mon Dec 11, 2017 3:13 am 
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I bet licensing Yamaha sound chips wasn't free either.


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PostPosted: Mon Dec 11, 2017 6:24 am 
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Espozo wrote:
Is this for real? :lol:

I'm afraid it is. Here's my write-up: http://www.chrismcovell.com/gbbooster.html

"Well, I plugged the GB Hunter in... the GB hunter logo scaled onto the screen, and (with a GB cartridge properly inserted), the 'Loading...' screen came on for a second. Then, the horror began.

The GB game started running, of course, but what came out of my TV's speakers was not GameBoy sound, but a horrible screechy 'song' played as a looped sample at about 4khz... So, the reports were true; this thing didn't emulate the GB sound at all. In fact, total silence is preferrable to this song... What were they thinking???"

Trivia time: the horrible sound from the GB Hunter seems to be a rendition of "That's the Way It Is", a C-64 tune. It's just a bit hard to recognize.

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PostPosted: Fri Dec 15, 2017 6:26 pm 
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Well, this is relevant to arcade machine hardware, although not the discussion of that Data East arcade machine: Do most of the arcade game boards from the late 80's and early 90's generally use some sort of (physically) standard sized rom chips? (Seems like piracy would be really easy though if this is the case, so probably not.) I've always wanted to own an arcade board, but while I regularly see deals for system boards with shitty games for less than $250, the games you'd actually want to buy the system for go for well over $500, with few exceptions. In addition, it's almost impossible to get game boards by themselves for some reason, unless the ratio of system pcbs to game pcbs is roughly 1:1. I'm hoping I can get a $50 eeprom programmer and a bunch of eeprom chips and make a few games; I don't know if I'm being delusional about this, because I've never had any experience with this exact sort of thing.

What would be really neat is a device that uses a USB port (or several) that splits the signal to be massively parallel to where you could put a wire in every slot for every rom chip on the game board. You could then hook it up to a Raspberry Pi and make a "SD to CPS1" or something like that. Probably wouldn't work for about 1000 different reasons though. :lol:

...Old systems with palette rom, I imagine, would actually be able to play 60fps, full color FMV then... :lol:


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PostPosted: Fri Dec 15, 2017 6:36 pm 
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Espozo wrote:
Seems like piracy would be really easy though if this is the case, so probably not.
Yup, it was a problem. Hence why so many later arcade boards have "unclonable" and/or "suiciding" parts.


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PostPosted: Fri Dec 15, 2017 6:43 pm 
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I don't think the CPS1 (which is mainly why the CPS2 exists) or Irem M72 and M92 do, or at least I really hope not, as these are the only boards I really have a strong interest in. R-Type and R-Type II (if you can even find it) are as expensive as hell, but I found a deal for "Pound for Pound" that uses the same board for only $100 (with free shipping :lol:): https://www.ebay.com/itm/POUND-FOR-POUN ... 0005.m1851


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PostPosted: Fri Dec 15, 2017 10:22 pm 
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I found that common 27C020 AMD eprom chips work with M92 game boards: http://www.jammarcade.net/irem-m92-double-repair-log-1/

According to this (http://arcadehacker.blogspot.com/2015/0 ... art-1.html) The video processor for each CPS1 game is on the game board itself? This (http://www.jammarcade.net/strider-conversion/) seems to cement that by saying:

Quote:
According to MAME, cpsb registers start at a base address of 0x800140 and end at 0x80017f, this is true for all cpsb PPU variants. But the actual addresses for each register changes between PPUs.

:| It's not impossible to make it work, like how this person is going through the rom and manually changing the pointers, but it's still more work than I would have hoped.

I haven't found anything about the M72, but I'm not getting all of these at once anyway.


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PostPosted: Sat Dec 16, 2017 7:59 am 
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Triple post! :lol: Because I'm not about to buy a $200 supergun, it occurs to me that the Jamma standard has a pins for three buttons, along with a start button. Luckily, so does this:

Image

Because the controller port is identical to a serial port (?) you could just get a male to female serial port cable and stick the wires from the Jamma harness accordingly. (I have no idea how the six button controller works)

Image

Your power supply is going to have to supply 5V anyway, so that's fine. The real problem seems to be a video converter; I'd have thought it'd be all be analog, but all the devices I've seen appear digital, which more than likely means there's going to be lag. :| Does anyone have any suggestions?

Edit: Wait, I'm an idiot, looking at the schematic, even with the standard controller, some buttons share the same pins somehow. Darn.

Edit 2: Actually, I'm not sure... I've found some stuff that seems to imply each button has one pin assigned to it, and I have no idea what "select" means on the above picture.


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PostPosted: Sat Dec 16, 2017 10:19 am 
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On the 3-button controller, "Select" is an output from the console, roughly analogous to $4016 D0 out on an NES or Super NES. It switches the A, B, C, and Start lines between two of the pairs of buttons. On the 6-button controller, it switches more lines if toggled multiple times within a millisecond. (Source)

Your JAMMA harness will need a circuit that toggles Select, latches the output in both states, and relays it to the system board.


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PostPosted: Sat Dec 16, 2017 10:35 am 
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...In other words, I need to find another solution for a controller. :| I could make a somewhat-ghetto arcade controller out of wood and screws from Lowes and it would be largely cheaper than any one I could buy, but I kind of want an actual handheld controller with a d-pad. An arcade joystick without a cabinet just feels off to me.

I can't believe how expensive some of this stuff is for people who don't know what they're doing. Individual parts, like a power supply or signal converter, are pretty cheap, but once you throw them altogether in a box, it eclipses the cost of the actual arcade pcb. Also, what's the fun in that? :lol:


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