[JoeDaDude]

The subtractive synthesis model which you describe, now done digitally, may be the most widely implemented model, but there are several other models that at least approximate what you are describing. For example Csound [1], which allows for lower level functions to be used in synthesis. However, there is a leap required to go from low level math to a functioning instrument that a composer or performer can use. [1] http://csound.github.io/