Going down the simulation rabbit hole

I would like to gain a better understanding of the physics of box design. I've decided the best way to do this is to attempt to simulate the problem in various ways. The problem I'm finding myself in right now is that I don't fully understand how to characterize the problem, or where to start.

My thought right now is to start by learning how to break down a given geometry into lumped element analysis and simulate on spice or similar. From what I've gathered so far though, it seems that the geometry of the box is boiled down into just its volume.

I guess what I'd like to ask, for anybody that has gone down this path, or has experience with simulating accoustics is for suggestions on reference material to understand the math that I'm working with, and how it's derived. I'd like to go about this in the most open-source way that I can, so it can be felt available to anyone else that has an obsessive curiosity.

My background is in software engineering, and I did some split step optics simulations in grad school.

Thanks for any input.