Inside of a Piano – Grand vs. Upright

Pianos are some of the most beloved and versatile musical instruments, capable of producing a wide range of sounds and emotions. The intricate mechanisms inside of a piano are responsible for its melodious tones and are a testament to the ingenuity of craftsmanship.

In this post, we will explore the components found inside both grand (horizontal) and upright (vertical) pianos, highlighting any differences between these two basic types of pianos.

How a Piano Makes Sound

piano hammer action

First thing first, let’s take a look at how a piano makes sound. A piano is a complex musical instrument that creates sound through a combination of mechanical and acoustic processes.

Key Action

When a pianist strikes a key, a series of actions and components work together to produce the beautiful tones associated with the piano.

The key is connected to a complex action mechanism. As the key is pressed, it activates a lever system that ultimately lifts a hammer. These hammers are covered in a special felt material. The hammer’s felt covering is designed to protect the strings from damage while transferring the energy of the strike to the strings.

String Vibration

Inside a piano, a set of strings is stretched over a wooden frame. Each key corresponds to a particular string or group of strings. The material of the strings is high-tensile steel wire, which gives them the ability to withstand high tension.

When the felt-covered hammers strike the strings with force, the impact of the hammer on the string causes it to vibrate. The strings’ vibration is what produces sound in a piano. The specific pitch and tone of the sound are determined by the length, thickness, and tension of the strings.


The soundboard inside of a piano acts as a resonator, making the piano’s sound rich and robust.

Dampers are felt-covered blocks that rest on the strings. When a key is released, the dampers come in contact with the strings, stopping their vibration and thus ending the sound.

The sustain pedal on a piano lifts all the dampers off the strings, allowing the sound to continue even when the keys are released.

In Summary

The sound of a piano is created by the interaction of the keys, hammers, strings, and the soundboard. When a key is struck, the hammer hits the string, causing it to vibrate and produce a musical note.

The size, tension, and materials of these components all play a role in determining the pitch, tone, and overall quality of the sound produced by the piano.

Common Components Inside of a Piano

There are several common components that play a fundamental role in both grand and upright pianos. These parts serve as the core elements responsible for producing the instrument’s beautiful and expressive music.


The soundboard is a crucial component in both grand and upright pianos. It amplifies the vibrations of the strings, allowing the instrument to produce a rich, resonant sound. The soundboard is typically made of spruce, chosen for its exceptional resonant qualities.


inside steinway grand piano
Inside of a Grand Piano

Piano strings are a remarkable engineering feat, with each string carefully designed and positioned to create the instrument’s distinctive and expressive sound.

The strings are usually made of high-tensile steel wire. This material is strong and has the ability to withstand the high tension required for proper tuning. The steel wire is further treated to improve its longevity and resistance to corrosion.

The length of the strings corresponds to the pitch of the notes they produce. Shorter strings generate higher-pitched notes, while longer strings create lower-pitched notes.


grand piano hammer action
Grand Piano Hammer Action

Piano hammers are a meticulously crafted component of the piano action, and their design and condition significantly influence the instrument’s tonal quality and responsiveness.

The keys connect to the hammers that strike the strings when the player depresses a key. Their construction and felt covering seriously impact the piano’s tone.

Piano hammers are typically made from several layers of tightly compacted felt. This felt is carefully chosen for its density and resilience. The outer layer of the hammer is covered with a softer, high-quality felt material, which comes into direct contact with the strings. The inner layers provide support and resilience.

The point where the hammer strikes the string is crucial. It must be precisely positioned to ensure the strings are struck evenly and avoid excessive wear. Normally, the piano regulation process adjusts the position of the hammers.


Dampers are felt-covered wooden blocks that rest on the strings. When the player releases a key, the dampers press against the strings to stop the sound.

Piano dampers are a vital part of the instrument’s action mechanism, responsible for controlling the duration and quality of the sound. Their precise regulation and maintenance are essential to achieve responsive and expressive performance, allowing pianists to create the nuanced and dynamic music that pianos are renowned for.


Pianos typically have two or three pedals.

  • The sustain pedal sustains the sound,
  • the soft pedal reduces the volume,
  • and the una corda pedal shifts the hammers to strike one or two strings, altering the tonal quality.

Key Differences Between Grand and Upright Pianos

upright and grand pianos

Grand and upright pianos differ significantly in terms of their design, size, and internal components. Here’s a summary of the major differences –

Size and Shape

The most apparent distinction between grand and upright pianos is their size and shape.

  • Grand pianos have a horizontal layout with strings extending horizontally.
  • Upright pianos have a vertical design with strings running vertically.

Grand pianos tend to be larger and more elegant, making them suitable for concert halls and grand rooms, while upright pianos are more compact and fit well in homes.

Sound and Strings

The soundboard and string configurations differ in grand and upright pianos due to their shapes and sizes. Therefore, they produce different sound quality.

Grand Piano

Grand pianos generally offer a more resonant and powerful sound because of their larger soundboards. This expansive soundboard allows for longer string lengths, especially in the bass section. Hence, the grand pianos produce deep, resonant bass tones.

Grands typically have three strings per note in the treble section and two strings per note in the bass section. The total number of strings in a grand piano can range from about 220 to 240 strings.

Upright Piano

inside of an upright piano
Inside of an Upright Piano

Upright pianos have a more compact design, resulting in a less pronounced sound. However, this can be an advantage in smaller spaces where a grand piano’s volume may be overwhelming.

Uprights have a smaller soundboard due to their vertical structure, resulting in shorter string lengths and a generally less vibrant tone.

The smaller upright pianos usually have one or two strings per note, depending on the model and design. This difference in string configuration is due to the upright piano’s vertical structure and the space limitations inside the cabinet.

Action Mechanism

While the basic action mechanism is similar in both types, grand pianos often feature a more responsive and precise action due to their horizontal layout with longer keys. This allows for greater control and expression in the music.

The weight and size of the hammers vary across different types and models of pianos. Grand pianos usually have larger hammers with more substantial felt, allowing for greater dynamic range and tonal control. Upright pianos may have slightly smaller hammers due to space limitations within the cabinet.

When you look at the inside of a piano, one of the obvious differences in the action mechanism is that the hammers of an upright piano hit the strings horizontally, while the hammers in a grand piano strike the strings upward.


Grand pianos are typically more expensive than upright pianos due to their larger size, superior sound, better materials, and craftsmanship. Upright pianos are more budget-friendly and practical for many households.

It is worth noting that digital pianos are usually much more affordable than acoustic pianos, even upright pianos. Nowadays, the sound quality and actions of digital pianos are very close to some expensive acoustic pianos.


Both grand and upright pianos house an intricate array of components that work together to create beautiful music. The choice between these two types of pianos often depends on individual preferences, available space, and budget.

Moreover, it is also worth considering a digital piano, depending on your musical objectives.

While grand pianos tend to offer a more expansive and resonant sound, upright pianos provide practicality and affordability, making them suitable for a variety of musical settings.

The inside of a piano, either grand or upright, the principle design and components are similar. However, each style of piano adapts to its respective design, allowing for an array of options for pianists and music enthusiasts.

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