Each cello need 15 coats of varnish, with each application requiring a full week to dry. Helffrich shuffles around his living room, the one where assorted wingback chairs are arranged in a semicircle.

The cello is probably the closest instrument to the human voice in terms of range and pitch. The form even resembles a human body (think Man Ray’s 1924 photo of Kiki de Montparnasse, called “ Le ...