That’s music to his ears

The two Steinway grand pianos on the stage in Sprague Hall dazzle the eye. Their music? That depends on the talents of graduate students, faculty, and visiting artists at the Yale School of Music. The musicians play in classrooms and studios and perform in concert venues on campus, but before they beguile audiences on the ivories, the piano must be readied for their touch.

This work is the domain of Erik Diehl, chief concert technician and curator who, with technicians Rob Crowson and Brian Daley, is responsible for making sure that 100 Yale School of Music pianos are in optimal sound shape at all times.

Tuning

Diehl walks on to the stage at Sprague Hall, places his kit — a black case containing 100 tools — on a chair and dons his black work apron. He opens his kit and pulls out his most frequently used tools, a tuning hammer, felt mutes, and felt strips. Diehl sits down on the piano bench and begins the tuning process by securing the tuning hammer (a lever that resembles a specialized socket wrench) to the top of a tuning pin. Each pin has a steel string coiled tightly around it and is threaded into a wooden block. Turning the pin to the left decreases the string’s tension and lowers its pitch; turning it to the right increases the tension and raises the pitch.

“When I tune a piano,” Diehl notes, “I adjust the first note to a pitch source, and then I make sure that the temperament octave, the middle section of piano keys, matches the pitch of that first note. When this is set, I sync the rest of the notes with the [middle section] temperament octave to achieve equal temperament. I place the felt mute between strings to silence them before I tune the outer strings.”

Voicing and regulation

Tuning is one of a four-part process that Diehl performs in his role. Voicing and regulating a piano, steps two and three, require him to pull out from the front of the instrument what is known as the “the action”, which houses the inner workings of the piano and the mechanism that causes the hammers to strike the strings when a key is pressed. Modern piano actions are often composed of over 8,000 individual parts that the maker, in this case Steinway, adjusts to factory settings.

When voicing the piano, Diehl focuses on the hammers, which are all different sizes, weights, and densities, and therefore affect musical sound. Voicing is about adjusting the density of the felt around the hammer heads to create an even tone. Diehl uses tools like voicing needles to soften the felts to change the sound when the hammer hits the strings. Softening the felts can create a darker tone, while hardening them can produce a brighter one. 

“Regulation is ensuring that the pianist has as much control as possible while playing —that the piano is operating at its full range of power,” adds Diehl. “Each musical note has 12 to 13 adjustments to conform to the pianist’s touch. Regulating also means bringing parts back to their factory settings if regular use has made them less efficient.”

Cleaning

The fourth part of Diehl’s process is making sure that the piano is always clean. He will use a special vacuum that fits in and around the parts of the instrument.

Diehl does not always work alone. He is often accompanied by pianists, especially before a performance, to bring the piano up to their standards of touch and tone. “My role here is to support the pianist,” said Diehl. “Anything I can do to make their lives easier is my goal, each and every day.”

All roads go through Astoria

Diehl was drawn to the piano as a child growing up in rural West Virginia. He studied piano performance and majored in music at Berea College in Kentucky. Diehl switched his sights to piano technology after graduating and attended the North Bennet Street School in Boston, clocking the 10,000 hours required for his craft. He then took a position with a piano rebuilding shop in Santa Monica, California, and later moved to the Steinway & Sons factory in Astoria, Queens, to work in the Concert and Artist Department before joining Yale in August 2023.