Tutorial:SynthBasics - jlearman/sfzwiki GitHub Wiki
The SFZ language assumes you know a lot about subtractive synthesis. This page is intended as a guide to help you learn about synths so you can understand the terms in the sfzformat site.
The first thing to know is called "subtractive synthesizers." This is the first type of synthesizer, immortalized by products by companies like Moog and Arp. It's called "subtractive" because it starts with an easily-generated waveform that has lots of high frequency components ("harmonics"), and you subtract the stuff you don't want. It's not really great at duplicating natural sounds, but it's amazing at creating new ones.
Online Subtractive Synthesizers
Probably the best way to learn about synthesizers is the way I did, back in the 70's, by playing with them and seeing what the controls do. Here's a nice online synthesizer that has the advantage that it calls most things by the same names that SFZ does:
One difference in terminology is that what it calls "VCA" (for voltage controlled amplifier) is what SFZ calls "amp" (for amplifier). Amplification (volume) is no longer controlled by a voltage, but rather by a digital signal, so the VC is no longer needed.
Here's another one I like (though it doesn't work on Mozilla): Juno-106, based on the Roland synthesizer of the same name from the early 80's. Actually, it's also a lot like my first synthesizer, its predecessor the Juno 60.