About the film
Pianomania is a 2009 German-Austrian documentary film by directors Lilian Franck and Robert Cibis. The film presents Stefan Knüpfer, a virtuoso piano tuner from the piano company Steinway & Sons, in his work with pianists such as Lang Lang, Alfred Brendel and Pierre-Laurent Aimard.
From the film's Wikipedia article (CC BY-SA 4.0).