Understanding the Una Corda Pedal:
Grand Piano Soft Pedal Regulation and Hammer Spacing
At The Artisan School, we spend a tremendous amount of time teaching technicians not only how to tune pianos, but how to truly understand all the other repairs and situaions you will run into when out in the field as a piano technicain. One area that often gets overlooked in standard piano technician training is proper una corda pedal regulation, also known as soft pedal or shift pedal regulation.
Understanding the Purpose of the Una Corda Pedal
On a grand piano, the una corda pedal does far more than simply make the piano quieter. When functioning correctly, it changes the tonal color of the instrument by shifting the entire action sideways so the hammers strike the strings differently. In most modern grand pianos, this means the hammer misses one of the three strings in a unison, reducing both volume and tonal density. However, some European pianos are intentionally designed with a different spacing philosophy where the hammers continue striking all three strings while contacting a different portion of the hammer felt to create a unique tonal character.
Preliminary Preparation Before Regulation
Before any regulation work begins, proper preliminary preparation is essential. This includes removing the action, lubricating the keybed and glide points with Teflon powder, inspecting the keyframe movement, checking spring tension, and making sure the action shifts freely and returns properly. Many technicians are surprised to discover that sluggish or incomplete soft pedal return is often caused by friction issues rather than actual regulation problems.
Adjusting Soft Pedal
Once the action is moving correctly, the next step is adjusting the pedal throw. Proper throw adjustment ensures the action shifts just enough to create the desired tonal effect without causing hammers to strike neighboring strings. Depending on the piano design, this adjustment may be located on the cheek blocks, along the rim, or underneath the piano within the trapwork assembly.
Hammer Spacing and Tonal Control
From there, hammer spacing becomes critical. In the middle sections of the piano, technicians typically space the hammers so the soft pedal causes the hammer to miss the far-left string. In the high treble section, however, many technicians intentionally center the hammer on all three strings to maximize tonal projection due to the shorter string length. Bass and bichord sections require their own spacing strategies as well, often positioning the hammer to strike near the edge of the felt rather than fully missing a string.
One of the most valuable parts of advanced piano technician training is learning how all these systems work together. Small details such as hammer travel, cheek block pressure, glide bolt lubrication, and even slight inconsistencies in string alignment can dramatically affect how the soft pedal performs. These are the kinds of refinements that separate average piano work from truly high-level pianocraft.
At The Artisan School, our goal is to help technicians understand not only the “how” behind piano regulation, but also the “why.” Whether you are learning piano tuning, advanced grand regulation, voicing, or complete piano repair training, developing an eye for these small mechanical and tonal relationships is what ultimately leads to mastery in the field of pianocraft.
If you are passionate about becoming a piano technician or improving your piano regulation skills, explore our training programs, mentoring membership, and live technician classes at The Artisan School.
