Peter Mitchell tells his class an anecdote about the two times he met cello legend Pablo Casals; this anecdote is a true incident that happened to another legendary cellist, the late Gregor Piatigorsky. This anecdote is paraphrased from Piatigorsky's autobiography, "Cellist".
The concert scene in the film is played at the Grace Rainey Hall at the Metropolitan Museum - the same stage where the legendary Guarneri String Quartet played their farewell concert after 45 years of playing together.
Catherine Keener said about Christopher Walken's role in the film and the way the other actors related to him: "He is the man. He's 'the dad.' And if dad is cool and feeling good today, we all feel good. We truly hated to disappoint him. We were always happy to see him. We wanted his approval. All of those things."
The trivia item below may give away important plot points.
In the final scene, after Peter Mitchell excuses himself and Nina Lee takes his place, three issues are shown being resolved. The first is when Robert and Juliette Gelbart get up and hug, thus reconciling after their fight. Then, Daniel Lerner closes his notes, and thus submits to the request to play Beethoven's piece by memory, as requested by Robert Gelbart. Finally, in response to this, Robert Gelbart closes his notes as well, but is also seen touching the front page of the notes. The fact that he touches "Violin II" indicates his acceptance of that role moving forward.