I am working on synthesized patches using a combination of additive and subtractive methods to create a digital orchestra. The goal is not to recreate orchestral sounds, but rather to create an instrumentation for polyphonic works that builds on principles from orchestral instrumentation of a classical orchestra - roughly the size of what is required for Beethoven's work.
I am currently building a string-like section from a single patch with a long sustain. I would then like to process this patch into easy distinguishable variations that mimic the relationship between the string instruments: violin, viola, cello, and double bass. The overall waveform for these instruments is to my understanding similar. However, the individual characteristics seem to be heavily dependent on the resonating body of each instrument. A viola is basically a larger violin. For a cello, however, I think the bow is broader and the strings have a different characteristic.
I am familiar with Karplus-Strong synthesis, but my goal is not a realistic string instrument. Instead, I would like to apply the principles that differentiate a family of instruments to create individual patches that belong to the same "section". To achieve this for strings, I think manipulating the characteristics of the resonating body - size and shape in particular - could be useful.
I have tried to use short reverbs, long unmodulated chorus and other variations on copying and delaying a signal to simulate different resonance characteristics. I also was somewhat successful in simulating the bow using enveloped noise and very short granular delays. Ideally I am looking for a VST solution or using mix buses and filters.
Are there any common techniques for simulating resonating bodies?