12 Feb

So today I’ve started on the clavichord project. But I haven’t touched a piece of wood yet.

The last time I built a clavichord, I got to the point where I was trying to build the sound-box and the bridge. I could not figure out the right shape for the bridge, and could not find any documentation online that explained why any particular shape was chosen.

The nearest I could come to it was descriptions of ribbing in guitars and how they affect tone.

But, because I like to know what I’m doing before I do it, I’ve decided to build a simulator that can simulate a clavichord’s sound-generation abilities without me needing to actually build it.

And if I build it right, I’ll be able to adjust parameters in the simulation (bridge positions, soundbox sizes, etc) dynamically to figure out the best possible parameters for what I want.

After thinking about it for a day or so, I think the right way to do this is with a mass-spring system, where the clavichord is represented as a massively dense system of nodes and springs, which allow me to apply virtual forces to things like strings and keys and see what happens.

What I hope is that the simulation will result in vibrations that I can translate into actual sound, so I can hear the simulated clavichord.

I’ve never done this before (has anyone?) so I’m starting from first principles.

The first principles in this case is a simple 1-dimensional mass-spring system, which I’ve built here. It simply simulates a weight hanging from an anchor, bobbing up and down on a spring until the bouncing is damped and the weight hangs still.

Tomorrow, I’ll work on building that into a 2D system. There is a very simply tutorial of 1D mass-spring systems here. Near the end, the tutor expands it to be 2D, but I don’t think it’s done correctly – doesn’t take into account diagonal stresses that trigonometry is required to solve.

I could not find a simple 2D tutorial, so will need to build that from first-principals tomorrow.