On this episode of the Dekoni Audio Padcast, we’re joined by Dave Friesema—co-founder and chief designer at Dark Matter Audio Labs, and a veteran engineer behind countless in-ear monitor projects at Etymotic and Westone. We unpack what actually makes an IEM sound “right”: driver choices, acoustic paths and bores, damping and filters, phase alignment, and why fit and tip selection can swing the response more than you think. Dave also explains how designers balance measurements with listening, the trade-offs of venting and isolation, and the unique challenge of building universal demo units for a product that’s meant to be custom-fit. Whether you’re a touring pro, a studio mixer, or an audiophile chasing a natural curve, you’ll come away with practical takeaways for dialing in your IEMs.