There are actually two ideas at play here. Manipulating a signal from a VCO, or any other 'analog' signal is called analog synthesis. These analog signals can be used as the source in other types of synthesis, including FM synthesis. FM synthesis tends to be done using digital signals because they are more stable, however.
Using high/low/band pass filters to filter your signal is called "subtractive synthesis" because you are subtracting frequencies from the original waveform.
Yes, some analog synths of lore (EMS gear IIRC) could actually create FM sounds, but the oscillators limited stability made it unusable for musical sounds.
AFAIK The latest generation of Yamaha FM synths (SY/TG77, SY99) could apparently use any oscillators including audio samples for FM.
Unfortunately FM synth always were notoriously hard to program, because of the lack of intuitiveness of the sound behaviour (as opposed to oscillators and filters), that finally led to their demise.
> Using high/low/band pass filters to filter your signal is called "subtractive synthesis" because you are subtracting frequencies from the original waveform.
You're right, that's the proper term. By the way the Synclavier was altogether an FM, substractive and addditive synth :)
Side note, I'm wondering why additive synthesis never really get any significant foothold (who used a PPG? a Kawai K5?).
You can replicate it well enough with just those two elements anyway.
The snare is just some white noise and a highpassed sinewave.
The bell definitely sounds like it has ring modulation. I seem to remember the cowbell being the hardest one to rip off. The toms were tricky as well.
On the other hand, my fake 808 had a dub siren built in, a tape delay, overdrive and it could do triplet beats. It was awesome. That whole lab class was most amusing.
Filtering a sine wave makes little sense, as you'll only end up altering the volume (unless you take the phase respone of the filter into account but this should be barely audible).
If you lack a VST plugin host, http://www.hermannseib.com/english/vsthost.htm is very bare-bones but does the trick for doodling away and http://reaper.fm/ by Justin Frankel (of Winamp fame) et al. is a more full-featured DAW that supports VSTs.