There is an interesting point to make regarding the “athlete” vs the “locomotive conductor” in re: cybernetics (in the academic sense, not the sci-fi sense).
In the case of the performer with an acoustic instrument, there is a very clear path of transduction for bodily kinetic energy (e.g. vibrating vocal chords, or an arm pulling on a bow tugging on a string, a lung exhaling into a resonating tube, a finger pressing a lever, an arm and a hand striking a membrane etc.) into auditory acoustic energy (vibrating air). This might be akin to your “athlete”, wherein their direct bodily action is transferred to eg a ball.
On the other hand, you are suggesting that the synthesist and synthesizer form a feedback network. Unlike the acoustic performer, the acoustic energy is sourced not from the perfomer’s body, but rather directly from the electrical grid (or chemical gradients in batteries) - in both cases though, somewhere along the line the energy is sourced from the sun. In your paradigm, the synthesist’s job is to steer the flow of this electricity along a path towards eventual actualization by the machine as sound. The synthesist responds to this auditory (and sometimes visual or tactile) feedback and adjusts the parameters of the system to continuously alter the sound produced. This a pretty classical description of a cybernetic system. Indeed, the root of “cybernetics” is the Greek κυβερνήτης ( kybernḗtēs), referring to the oarsman steering a boat (edit: can’t find a reference now but a used to think that there was a specific example of this root in reference to the person guiding a boat across the river Styx - but perhaps that is my over active imagination…). The comparison to a conductor seems fair to me.
On some level there is a qualitative difference in some of the parameters of practicing due to this difference in energy sources for transduction into acoustic vibration, however I think it is probably more productive to think about where the similarities lie.
For instance, your description of a conductor guiding a system and responding to inputs and outputs would be just as apt for the experience of a performer - whether acoustic or electronic - in the context of improvisation, whether in a group or solo setting. Similarly, the precise gestures of an acoustic performer are relevant to an electronic musician - whether it is a DJ executing a series of transitions in quick succession, or a synthesist using a touch controller, or the embodied knowledge of a performer intuitively knowing where all the different knobs/faders etc may be and seamlessly flowing from one point to another, or a Monome user executing a series of gestures in a Grid app.
Furthermore, in the case of performance, the electronic performer has the same challenge as the acoustic performer in considering how to relate to the audience and what degree of control or freedom to give themselves in their bodily actions, whether it be posture, facial expressivity, movement to a rhythm etc. The electronic performer has the added challenge of deciding whether or not to even try to express a relationship between their body and the music vs accentuating the abstraction between the two.
While it’s true I think that there aren’t exact analogs between eg practicing scales or drumming rudiments in the context of a synthesizer, I do think there are absolutely direct analogies between acoustic practice and electronic practice, especially when considering things from the improvisational, collaborative, and compositional perspectives. Furthermore, where there are differences, it can be enriching to try to take forms of practice that are easy to model in one domain and attempt to create a version of them in the other. For instance if the direct link between bodily energy and acoustic output is important to you or something that you enjoy, try seeing how you can integrate that more fully into your modular system. You might try using contact microphones, or motion sensors, a Kinect, a microphone or breath sensors, etc.
Edit: here’s a link to a very excellent collection of papers on the relationship between the body and sound in the context of electronic music composition and performance.
