Prototyping with Acrylic Spheres and Electret Capsules

I’ve been back in the lab this week, doing some more hands-on prototyping — one of my favourite parts of the process.

This time, I’ve been working with 60mm acrylic spheres and fitting them with three 6mm electret condenser capsules. These little capsules have a surprisingly full frequency response — a true 20Hz to 20kHz — which makes them great for capturing detailed, natural sound in a compact form.

What I’m really trying to figure out is how the shape and material of the acrylic ball, along with the multi-capsule layout, influence the overall sound — things like frequency response, polar patterns, and noise performance. To get a clear picture of what’s going on, I’ve been measuring everything with an Earthworks M30 reference mic and my Genelec monitors. It gives me a reliable picture of what’s really happening, without the tools colouring the results.

It’s still early days, but these sessions always reveal something useful — a new idea, a small adjustment, or just a better understanding of how these components interact. I’ll keep refining things and will share more as the design takes shape.