Building a Macrophone
By Brian House
Thursday, 07/28/2022
While I'm here at Djerassi, I'm working on my Macrophones project — essentially huge microphones that pick sound far below our range of hearing. I've pieced together the design from the literature on volcano sound and nuclear warhead test detection. My version is lightweight and portable, but there's a lot of repetitive (meditative?) labor that goes into the construction of the wind filters (wind interferes with infrasound, so the big challenge is separating out the small pressure changes I want to record from the chaotic gusts that roll over the hills).
I worked with Geordi Helmick at the fab lab at University of Oregon's Knight Center to mill the manifolds for each of the macrophone filters, which have worked out great, way quieter than my previous DIY version. I'm using my special sauce combination of whiffle balls, porous stones, and fake fur to construct filter inlets, so for a few days I was just sewing them together. Turns out a critter of some kind (deer, gopher, hawk?) liked the look of them and bit off a few before I raised them off the ground. Shout-out to Tim Devoe for letting me take over the workshop assembling the wind-trapper sails.
I strung three of these (three-channel audio) together in the field for kind of a tensegrity vibe, which took some doing, but there's no nicer place to do it.
More to come on the electronics and audio side of things when we actually get to the listening.
