Saturday, April 11, 2015

GEEKSPEAK U: The Yamaha FM Chips of Gaming - Part 6 of 12: OPL Intro / YM3526 (aka OPL)

We've looked already at the OPM chip, and at the OPN line of chips in this series. The last series of chips that we'll focus on is the OPL line. The OPL line was mostly used on computer sound cards (such as the Ad-Lib, and Sound Blasters), but also did show up quite a bit in arcade games (mostly in conjunction with a YM2203 - OPN), and the budget version of the OPL line, the OPLL (YM2413) did show up in home gaming.

Where the OPM and the OPN line have quite a lot more in common than distinct, the OPL line is quite a bit of a departure from the OPM/OPN chips. And as we'll see, that will involve some MAJOR weaknesses against OPM/OPN, but also some pretty serious advantages as well. While the first three chips in the OPL line we will look at are widely regarded as inferior to the OPM/OPN chips, the final two OPL chips we will look at are widely regarded as quite superior to them.

The thing the first three chips in the OPL line (YM3526 - OPL, YM3812 - OPL2, and YM2413 - OPLL) all have the following in common: a) they are ONLY two-operator per channel, which means they can't do the more complex, nuanced FM that the four-operator OPM and OPN chips can do, and b) what they have going for them is they have a higher FM channel count than any of the OPM/OPN chips (plus another set of advantages that we'll get into with the OPL2).

All three of these chips have the same channel counts and options: They can either have nine channels of non-percussive FM instruments, or they can have six channels of non-percussive FM instruments PLUS five channels of FM percussion (also "canned" like the OPNA, only FM, rather than ADPCM) for a total of eleven channels instead of nine. And it's all pure FM (since none of the chips in the entire OPL line have any kind of PSG, and only the very last one (YMF278 - OPL4) had any kind of sampling capabilities.)

What separates the OPL from the OPL2 and beyond is that the OPL can only use sine operators like the OPM and OPN chips (but again, only 2-op, instead of 4.)

So, like the OPN and OPM, it's limited to just sine operators on the one hand, while like the OPL2, and OPLL, it's limited to just two operators per channel, on the other.

While this is indeed a "worst of both worlds" situation OPL found itself in, it also makes the chip really interesting and valuable as ANY sound that can be made by the OPL can also be made by ANY other chip in our series. So it makes a GREAT baseline referent for FM music - if you hear a sound on any other chip that sounds like a sound you heard on the OPL, then regardless of the additional capabilities of that chip, you know you're hearing a two-op, sine-only voice). It also means that ANY of the chips in the series can make sounds that this chip can not (so if you hear a sound that you haven't heard on OPL, there's a very good chance that it's something other than a two-op, sine-only voice).

In this way, the OPL is THE MOST basic chip of the entire series in that it is the one that is the most limited in terms of its FM generating capabilities on a channel-per-channel basis. However, once again, its saving grace is that it has such a high number of channels - three-way tying for a first place that would not be bested until the advent of the OPL3. By contrast, the OPN could do complex 4-op FM, but only had a paltry three FM channels (one third the OPL's massive channel count). Hence why these two chips were often paired together in the arcade.

Anyway, here are two games that use just the OPL for music - Terra Cresta, and Booby Kids. In fact, these are the only games I could find besides Fire Trap which I could confirm ONLY uses OPL for music. I will include Fire Trap as well, but it'll be actual game play rather than a music video, meaning it'll also have sound effects.

Here's Terra Cresta

Here's Booby Kids

And here's Fire Trap - but again, you're gonna have to deal with sound effects, and the like. Sorry I couldn't find a music-only video.

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