There are several ways of expressing spherical volume, other than just spherical surface lattices. Spherically placed spicules and hypercone curves are a couple of different expressions. Maybe it would be best to use all possible options in the same system, where certain qualities in the sound trigger an appropriate visual response. One of the qualities of music that makes it interesting is the internal structure of a piece. For example, with the action taking place on a ribbon that rotates around the surface of cylinder, shrinking toward the centre with time.
Notes currently being played are in the foreground and consist of modulations to a flat sheet.
The sheet curls away around the cylinder, wrapping around again and again as the radius shrinks. I imagine that a fugue would look quite impressive playing in this way, with new layers of structure building and complementing the previous ones. There are any possible mappings from the music into three-dimensional forms. It might be interesting to see a piece of music with several voices as being a constellation of changing forms, one for each voice, that interact in some interesting way, at times merging together to produce a single effect. In addition, loudness might be well represented by the size of the form, rather than by colour.