It all started with an enquiry from Nevada: A customer wanted to know whether our acoustic fabric would be dustproof enough to protect a couple of Bose F1 Arrays from exposure to dust during this year’s Burning Man festival. Good question. We didn’t have any empirical data, as we’d usually focus on sound permeability and translucence (or rather the opposite) in the development of our speaker fabrics. But the question piqued our curiosity and we wanted to come up with a proper solution. We decided to use superfine flour as an imitation of the dust in Black Rock Desert. Not the worst idea: Marc-Antoine from Nevada replied that “superfine wheat flour is a good approximation of Burning Man’s dust.”
The core of our test setup consisted of a piece of our stain-resistant and water-repellent Acoustic Cloth 2.0, an empty cardboard box, and a DIY “flour cannon” made of a cardboard roll core and several bits and pieces. We pointed the “cannon” to the speaker cloth at a distance of about 20 cm. Dried pressurised air at about 80 psi from our workshop was used to propel the flour towards the fabric. The measured air speed (and, consequently, the exit velocity of the flour) at a distance of about 10 cm from the cardboard tube was 27 knots (which equals 50 km/h or wind force 6). Not bad, eh?
We wasted the first pack of flour to find that one layer of fabric isn’t sufficient in our view. We weren’t happy with the amount of flour that went through. So we modified the setup and attached two layers of fabric. The distance between the two layers was about 1.5 inches and the frame with the first layer was slightly tilted to prevent the flour particles from building up between the two layers and instead simply drop to the ground. Admittedly a somewhat shaky impromptu installation that wouldn’t meet the requirements for whatever ISO certification, but good enough for our purposes.
The result of this second round made us happy, as there were only very few particles still going through the two layers of speaker fabric. We found just a little dust on the ground of the box, after we’d propelled another full pack of flour towards the front of the construction and finally cleaned both with an air nozzle before opening the box.
We’ve uploaded a video of this test on Youtube, so why not have 90 seconds of fun, watch this bonkers and weird dustproofness test, and judge for yourself.