You would be forgiven for thinking that the semi-spherical bulb [Len], from the Bellowphone channel, is holding is a toilet bowl float. It is a bellows of his design that is similar to the squeezable part of a bike horn but is more substantial and less irritating at six in the morning. These rubber squeeze balls are old-school in the best way, and craftsmanship rolls out from every second of his videos. The backdrops to [Len’s] videos are alive with tools, materials, examples, and instruments the same way our offices and maker spaces erupt with soldering irons, LEDs, and passives.
His video walks through all the steps to make latex bellows starting with a rigid stemmed bulb and painting it with latex. This takes a bunch of coats with the associated drying time, so if you need a lot of bellows, you will want multiple bulbs. After coating of latex, we move to the contraption known as the Snout Master 5000. The SM5K looks like a wooden jig held in a table vise, but it is a purpose-built over-engineered chuck with four ball bearings held in a vise. When the latex is thick enough, the form is removed, and the bulb is repaired, then, more coats. Each ball has roughly twenty layers, and with three hours between coats, this is a weekend job at a minimum. Good things come to those who coat. The final steps are boiling the bulbs and adding a silicone preservative. They can last up to a decade with proper maintenance.
We see lots of electronic and automated instruments here, and spherical balls are definitely on the human interface spectrum, but the techniques we see from [Len] would allow anyone to design their own bellows more conducive to mechanization. [Len] says one of his inspiration is [Harry Partch] and his Blo-Boy, an organ powered by fireplace bellows. We think these squeeze balls are even better.
Researchers from the University of Sussex used 3D printing for a modular approach to acoustic lens design. 16 different pre-printed “bricks” (shown here) can be assembled in various combinations to get different results. There are limitations, however. The demonstration lenses only work in a narrow bandwidth, meaning that the sound they work with is limited to about an octave at best. That’s enough for a simple melody, but not nearly enough to cover a human’s full audible range. 
