I just saw this… weird yet riveting… documentary on Netflix. If follows the trials and tribulations of Stefan Knüpfer, the senior piano technician for Steinway in Germany, as he meets with virtuosos to prepare their instruments for concerts and recordings. They all have different ideas how their pianos should sound, and part of the fun is their attempts to convey these ideas verbally to Knüpfer. Because in lots of cases there isn’t language specific enough to communicate their meaning. At times they resort to physical gestures.
It also has a very carefully and beautifully recorded sound track, so you can in most cases hear the issue the pianist is trying to address. One mentions that on playing a note that sustains and fades out, the last moments before the sound disappears altogether introduces something “off”, and you can hear it. In another case, Stefan places a series of baffles on a piano to change its character for a particular concert hall, and you can hear the changes from one baffle to the next.
I do wish there were more actual performances, but they are not really the focus of the show. It’s all about the preparation and interactions between artists and technicians. Plus, you get an almost unprecedented view at the mechanics of grand pianos.