I have never seen a tutorial. I've scoured a lot of forums, and read about how the team at Yamaha made the original presets. Most people never bother to design sounds. It's more tedious and frustrating than subtractive synth sounds.
First step is finding a capable FM synth you like with a decent user interface. Dexed, NI FM8, Arturia DX7 V, or maybe even Reaktor. (Edit: It’s obvious to me that you shouldn’t buy a Yamaha DX-something to do sound design, but just to make it clear, don’t do that. The user interface is abominable. Just get Dexed if you don’t know what you want.)
Build your sound up by adding "partials" or "tones", or whatever you want to call them. Start with two operators, with one chained to the next. Explore the space of ratios (start with 1:1) and modulation levels. Once you get a handle on some part of the sonic space, consider adding a third operator at the back, i.e. if your operators are A -> B -> C, and C is the output, then A is the one you're adding. Experiment with ratios and modulation levels, and consider this a way to expand the space you've already explored.
You'll find that most of the modulation values are either too subtle to notice or noise that you just can't stand. If you're at a point where the middle ground between subtlety and noise doesn't have the sound you want, that's when you might add the third operator.
With these partials, you can build up the sustain and attack of your sound separately. Experiment with using different timing for all of the envelopes.
You can tell that a lot of sounds are made from a smaller set of partials that have been recombined. For example, the classic DX7 rhodes sound is made up of an attack and sustain partial, and these partials have been reused and recombined with tons of other partials to make sound variations.
This is why I'm not fond of the DX-11, Ad Lib, or other 4-operator systems. They have the "FM sound" but you're really quite limited building your sounds. If you have a partial made with three operators, and you want to add something to it, you have to share operators or use a pure sine wave.
While 6-op definitely gives you more flexibility than 4-op, I find 4-op with non-sine operators more than usable. Examples include the YMF262 (OPL3), TX81Z and of course the digitone.
It depends, but I get what you mean. I love all the basses a plucky sounds I can get with that synth. also doesn't need a lot of post processing to cut through the mix.
First step is finding a capable FM synth you like with a decent user interface. Dexed, NI FM8, Arturia DX7 V, or maybe even Reaktor. (Edit: It’s obvious to me that you shouldn’t buy a Yamaha DX-something to do sound design, but just to make it clear, don’t do that. The user interface is abominable. Just get Dexed if you don’t know what you want.)
Build your sound up by adding "partials" or "tones", or whatever you want to call them. Start with two operators, with one chained to the next. Explore the space of ratios (start with 1:1) and modulation levels. Once you get a handle on some part of the sonic space, consider adding a third operator at the back, i.e. if your operators are A -> B -> C, and C is the output, then A is the one you're adding. Experiment with ratios and modulation levels, and consider this a way to expand the space you've already explored.
You'll find that most of the modulation values are either too subtle to notice or noise that you just can't stand. If you're at a point where the middle ground between subtlety and noise doesn't have the sound you want, that's when you might add the third operator.
With these partials, you can build up the sustain and attack of your sound separately. Experiment with using different timing for all of the envelopes.
You can tell that a lot of sounds are made from a smaller set of partials that have been recombined. For example, the classic DX7 rhodes sound is made up of an attack and sustain partial, and these partials have been reused and recombined with tons of other partials to make sound variations.
This is why I'm not fond of the DX-11, Ad Lib, or other 4-operator systems. They have the "FM sound" but you're really quite limited building your sounds. If you have a partial made with three operators, and you want to add something to it, you have to share operators or use a pure sine wave.