Monday, April 13, 2015

GEEKSPEAK U: The Yamaha FM chips of Gaming - Part 10 of 12: YMF262 (aka OPL3)

OPL3 is based on OPL2, but has twice as many total channels (18 2-op channels), and a total of eight operator waveform options (including all the ones in the OPL2 plus an alternating sine, a camel sine, a plain square, and a logarithmic saw.)

The most exciting thing about the OPL3, though is that instead of being restricted to just 2-op per channel, it could manage 4-op, but at a cost to channels. Here are the four possible channel configurations for OPL3:

a) 18 2 op instrument channels (drum mode and four op mode off)

b) 15 2 op instrument channels plus five FM percussion channels (drum mode on, four op mode off)

c) six 4-op instrument and six 2-op instrument (drum mode off, four op mode on)

d) six 4-op instrument, three 2-op instrument, and five FM percussion (drum mode and four op mode on)

Looking at all of this on paper, I would say that makes the OPL3 the most powerful chip of all the ones we've looked at in terms of its FM capabilities. But a couple of doodies in the cheerios before we hand over the crown.

1) This chip could still not sample, and unlike the OPM which makes up for this deficit by teaming up with sampler chips, I don't believe any such teamwork happened involving an OPL3, so it's still just basic FM percussion.

2) PC Games that used OPL3 didn't really "use" OPL3, instead, they basically just ran OPL2 instructions for compatibility. There may be some PC game out there that totally revamps its soundtrack to really utilize the OPL3...but everything I've experienced has just been OPL2 in stereo.

You might occasionally find a soundtrack that seems to sound better than what you'd expect from an OPL2, where you hear some things that you think might be the OPL3's enhanced feature set, but without having an OPL2 version to compare it to, there's still some doubt to whether this improves upon it at all. And even if it does, that there's so much uncertainty that it does still tells you it's well underutilized.

Here are two full soundtracks, as well as a track or two from a third game that are all running on OPL3. The first one - Rise of the Triad, that one sounds like it could be taking advantage of the OPL3 a little bit. Descent (of which we're only hearing a couple tracks) also sounds like it could be benefiting a little bit. Warcraft, our middle example just sounds OPL2 to me.

On the other hand, with OPM, programmers were squeezing every amazing little trick out of that chip in the Arcades and X68000 that they could. So even though the OPM is technically inferior to the OPL3, I feel that it yielded much better final results (at least compared to official PC games "using" the chip).

Once again, you be the judge.

Now, there have been chip artists that have more recently used the OPL3 to much fuller potential and with simply jaw dropping results. If comparing YM2151 OPM Arcade and X68000 games to Soundblaster PC games gives the false impression the OPM is a more powerful and capable chip than OPL3 (and let's be fair - it does), then hearing what these chip artists have done with the OPL3 in the days since will set the record straight.

When REALLY used, OPL3 really is the premier FM chip. Here's my proof - taken from the works of David Cohen (aka Diode Milliampere) - all of these are done 100% in OPL3:

Anyway that is OPL3 as it was misused by actual PC games, and has since finally come to be fully utilized by loving craftsmen close to two decades later.

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