Piano Strings — Complete Guide

A typical piano has 230–240 individual strings, collectively under approximately 18–27 tonnes of tension against the cast iron frame. Strings in Singapore are affected primarily by humidity — promoting oxidation of steel treble strings and corrosion of copper-wound bass string windings. Full restringing of an upright piano costs S$1,800–S$3,500. For a grand piano: S$2,500–S$5,000+. Individual string replacement is S$30–S$80 per string.

Three String Sections

Treble Section — Plain Steel Wire

The top 2–3 octaves of the piano use plain, uncoated high-tensile steel wire. In the highest treble, three strings are assigned to each note (called a unison or trichord). These are the thinnest strings, under the highest tension. The exact wire gauge is specified by the piano manufacturer for each note — a replacement wire must match the original specification precisely to produce correct pitch and tone at the correct tension.

In Singapore, treble strings are susceptible to surface oxidation (rust) from sustained high humidity. Surface rust changes the string's resonant characteristics and can cause breakage under tuning tension. Lifespan in Singapore: 30–50 years in air-conditioned environments, shorter in uncooled rooms.

Tenor Section — Plain Steel Wire

The middle register strings use slightly heavier steel wire than the treble. Two strings per note in much of the tenor section (bichord). The bass break — the point where the string construction changes — is a critical acoustic boundary that affects tone colour transition from tenor to bass.

Bass Section — Copper-Wound Strings

The lowest notes use strings with a steel core wire overwound with copper. The copper winding adds mass (which lowers pitch) without adding length, allowing the piano to produce deep bass without requiring impractically long strings. Many bass notes use a single string per note (monochord). Bass strings are custom-wound to specification for each piano model — they cannot be purchased off-the-shelf.

Bass string winding failure is the most common string problem in Singapore. The copper-steel interface corrodes in Singapore's humidity, loosening the winding from the core. Symptoms: muffled, dead bass with no sustain; in severe cases, a buzzing sound on the bass note.

How Piano Strings Produce Sound

A piano string is struck by the hammer, which sets it vibrating transversely (sideways). The vibration frequency is determined by three factors: string length (longer = lower), string tension (tighter = higher), and string mass per unit length (heavier = lower). Piano string design balances these three parameters across 88 notes. Strings vibrate at their fundamental frequency and simultaneously at harmonics (multiples of the fundamental), which produce the overtone spectrum that characterises piano tone.

The vibration transfers through the bridge into the soundboard, which acts as a large amplifying membrane. Without the soundboard amplifying the string's vibration, the sound would be barely audible — the soundboard projects the sound into the room.

When Piano Strings Fail

Signs That Strings Need Attention

• Visible rust or brown discolouration on treble strings
• Dead, thudding bass with no sustain (bass winding failure)
• String breakage during tuning
• Multiple broken strings in a short period (general wire weakness)
• Dull, lifeless tone overall despite recent regulation and voicing
• Piano that will not stay in tune even after full pitch raise

When Individual Replacement Is Appropriate

Single or small numbers of broken strings (1–5) are replaced individually. A broken treble wire is straightforward. Broken bass strings must be custom-wound and take 2–6 weeks to arrive. Individual replacement is appropriate when the rest of the string set is in good condition.

When Full Restringing Is Appropriate

Full restringing is recommended when strings show widespread rust, when more than 10–15 strings have broken, when the piano is over 60–70 years old with original strings, or when a full restoration is being undertaken. Restringing a piano that still has some healthy strings mixed with bad ones will create a tonal inconsistency between old and new strings for 12–18 months while the new strings settle.

The Restringing Process

Step 1 — Measurement and Parts Sourcing

Before strings are removed, each string is measured: length from hitch pin to tuning pin, diameter at multiple points, and winding specification for bass. These specifications are used to order replacement wire of matching gauge and custom-wound bass strings.

Step 2 — String Removal and Cleaning

Old strings are removed, tuning pins removed, and the entire iron plate, pinblock area, and hitch pin area cleaned. Often new tuning pins of slightly larger diameter are installed to restore proper pin torque in an ageing pinblock.

Step 3 — New String Installation

New wire is coiled onto tuning pins and hitched to hitch pins to specified tensions. Treble strings are pulled to rough pitch. Bass strings are installed individually.

Step 4 — Pitch Stability Period

New strings stretch significantly at first. Multiple pitch raise sessions are needed over 2–6 months to bring the piano to stable pitch at A440. Typically 2–3 pitch raise sessions in the first month, then quarterly for 6–12 months. Long-term tuning stability comes only after this settling period.

Singapore String Replacement Costs