As we age, our hearing slowly but surely slips away. Time turns down the decibels.

But what, exactly, does that aging-of-the-ears sound like? What would it sound like to go, in an instant, from the hearing of a 20-year-old to the hearing of a 90-year-old?

In the vocabulary of frequencies and decibels, what does normal hearing loss sound like?

In the Goodhertz audio lab in California, Goodhertz founder Devin Kerr does the majority of his critical listening at the mixing desk.

In August of 2012, after months of working on CanOpener Studio, and a lifetime of listening to music mostly on headphones, I got my first opportunity to visit the lab and hear music the way Devin does, at that desk, on a pair of professional-grade speakers — a highly controlled acoustical environment, tuned for his professional tasks (mixing, mastering, algorithm-designing).