The series, which includes 10 concerts in the upcoming season, has been free since 1938. Starting next month, tickets will cost $20 each.
In a letter sent to patrons, the museum said that "costs...have increased to a point where we must turn to the audience for help or face the prospect of reducing the number of concerts or canceling them altogether. Given the small size of our hall, the modest charge we have to institute, $20 a ticket, will only partially cover our rising costs."
A notice about the change on the Frick's web site notes that the music can be heard from the museum's Garden Court, outside the 175-seat hall, and that no tickets are required to listen from the court.
The next concert in the series is the New York recital debut of violinist Ilya Gringolts on July 13.