Grand Piano Repair vs Upright — What's Different?

Grand and upright pianos share the same basic function but their actions are fundamentally different mechanisms. Grand piano regulation costs S$400–S$700 versus S$200–S$500 for upright. This is not padding — grand actions are significantly more complex, have more adjustable parameters, and require more time to regulate correctly.

The Key Difference: Gravity vs Springs

In an upright piano, hammers are thrown horizontally at vertical strings, and they return under spring pressure — specifically the hammer return spring. The action is relatively compact and uses springs for most return functions.

In a grand piano, hammers are thrown upward at horizontal strings and return by gravity — the repetition lever catches the hammer as it falls back, resets it to ready position, and allows rapid repetition without fully releasing the key. This gravity-return repetition mechanism is what allows grand pianos to repeat notes much faster than upright pianos (up to 14 repetitions per second vs 3–4 for an upright). It also means there are more precision-adjusted parts per note — and more things that can go out of regulation.

Grand Piano Regulation — What Is Adjusted

Grand piano action regulation involves setting (per note, for all 88 notes):

• Key height and level
• Key aftertouch
• Hammer height and travel distance
• Let-off (escapement) distance
• Drop (hammer drop height after let-off)
• Repetition spring tension
• Repetition lever height
• Check height and check distance
• Damper timing (damper lifts at correct key depth)
• Hammer line (all hammer shanks aligned consistently)

A complete grand regulation takes 6–12 hours for a skilled technician. It is not a quick service.

Common Grand Piano Problems in Singapore

Humidity Effects on Grand Actions

Grand piano actions removed from the piano for service reveal extensive felt bushing swelling in Singapore's climate. The repetition lever felt, knuckle leather, and flange bushings all swell and tighten. This changes the repetition function — the piano may feel sluggish in fast passages, and notes may not repeat cleanly.

Damper Problems

Grand piano dampers sit on top of the strings and are lifted by the key action. In high humidity, damper guide rail felt swells and impedes free movement. This causes dampers to lift unevenly or too early, affecting sustain and chord pedal behaviour.

Soft Pedal Mechanism

The grand soft pedal (una corda) shifts the entire keyboard and action slightly to the right so hammers strike fewer strings. The shift mechanism has felt-lined parts that affect both feel and noise. In Singapore, the shift mechanism sometimes becomes sticky or noisy from humidity effects on the felt.