The word dobro means good in Slovak, but it also stands for the Dopyera Brothers, a family name stamped onto one of the most distinctive instruments in American music. This episode explores how John Dopyera, a Slovak immigrant and instrument repairman, set out to solve a 1920s physics problem: acoustic guitars were being drowned out by horn sections in dance bands before electric amplifiers existed. His answer was to embed spun aluminum cones inside the guitar body, creating the tricone resonator patented in 1929 with the National String Instrument Corporation.

When National's directors refused to build a cheaper single-cone model for working musicians, Dopyera walked out, founded the Dobro Manufacturing Company with his brothers, and discovered National owned the patent on his inward-facing cone. His workaround, an outward-facing cone with ...