Ah, yes, Raiden II sounds like its music came from a classic FM chip. Probably the popular Yamaha one which was standard on sound cards (Adlib, Sound Blaster, etc) for a long time.
… google …
Oh, not quite. The Adlib chip was a YM3812, but Raiden used a YM2151. Pretty close though. The PC version probably used the Adlib anyway since that’s what would have been available.
I don’t have a FM synthesizer, but a friend offered their Volca FM for cheap and it’s vaguely tempting. I like the sound of traditional analog synths better overall though. To me, frequency modulated digital synthesis sounds like the texture of plastic, the musical equivalent of paintings made only with pastel colors, like visiting a display home where every piece of furniture is brand new and every last detail is staged to make the house look lived-in despite being completely devoid of life. There’s something nice at times about the artificial clean-ness, but most of the time I prefer the scratchy dirty rawness of a subtractive analog synth.
While FM synths meticulously build up sounds one sine wave at a time, producing a very clean sound with a tidy spectral graph, what I used is nothing like that. The subtractive analog synth approach is to belch out all the colors simultaneously into a giant spectral rainbow from one horizon to the other, but filter out some of it before it hits the canvas.
Mathematically, square waves are the sum of an infinite series of sine waves at harmonic intervals. You can think of it kind of like the ripples caused by throwing a rock into a still lake. But of course that’s too simple, so most synthesizers provide lots of ways to make the canvas quite a bit dirtier than just a single square wave. It’s harmonics on top of harmonics as far as the eye can see, interference patterns, like a bunch of people throwing rocks into the same lake all at once. This makes really massive sounds which totally fill the sonic space. Then filters contain the mess, somewhat, by dynamically changing the shape of the lake. This cuts out some frequencies while amplifying others. It’s messy and fun.
Good FM can be really good though. For example, “Cave Bouncer” by my friend tenfour:
That requires more precision than I generally care for though. I typically paint the broad strokes and then get bored and move on.