How does a piano work?

The acoustic piano is made up of a variety of internal mechanisms, namely the strings, hammers, dampers, and soundboard. In essence, the pressing of a key triggers a hammer to hit the appropriate string, which then creates vibrations through the soundboard, causing the piano to sound.

Strings

An acoustic piano’s strings are made from high-strength steel that varies in length, thickness, and material to produce different pitches. Bass notes, for instance, require longer, thicker strings, often wound with copper. While treble notes rely on shorter, thinner ones. 

Hammers

The hammers are the more complex parts of a piano. Made from wood and covered in felt, they hit the string and then fall away quickly, allowing the note to sustain itself. The sustain is controlled by an escapement mechanism, which ensures the hammer is released from the strings immediately after striking.

Grand pianos use a double escapement system, allowing the keys to be pressed rapidly – essential for expressive and fast playing. 

One thing to consider with acoustic piano hammers is that the felt compacts over time, affecting tone quality. A tuning technician can adjust this by softening the felt to create a more balanced sound. 

Dampers 

Dampers in an acoustic piano control sound by stopping string vibrations when a key is released. Each damper consists of a felt pad that rests on the strings and lifts only when a key is pressed. This allows the strings to vibrate freely while the note is sustained. When the key is released, the damper returns to its position, silencing the sound. 

Dampers are a crucial part of the piano – without them, the instrument would produce a continuous blur of overlapping tones, producing a messy sound. 

Most keys have a damper, except for the higher-pitched strings, as their vibrations naturally fade quickly. If you don’t want the strings to be dampened, the sustain pedal is there to lift all dampers and let the notes ring out.

The soundboard 

The soundboard in an acoustic piano amplifies the vibrations of the strings and helps shape the instrument’s tone. When a hammer strikes the strings, their vibrations travel through the bridge and into the soundboard, which then resonates to project the sound. 

Soundboards amplify the piano’s volume and warmth. They’re typically made from high-quality wood, such as spruce, and feature attached wooden ribs to help distribute vibrations evenly. Without a soundboard, the piano’s strings would produce only a faint sound instead of the rich, full-bodied tone we associate with the instrument. 

Pedals

Piano pedals provide greater control over the instrument’s sound and dynamics. We’ve mentioned the sustain pedal (the rightmost pedal) – this lifts all the dampers, allowing notes to sound for longer after the keys are released. 

The sostenuto pedal (the middle pedal) sustains only the notes that are held down when the pedal is pressed, while all others remain unaffected. This is particularly useful for sustaining bass notes while playing staccato in the treble. 

The una corda pedal (the leftmost pedal) softens the sound, though its function varies depending on the type of piano. On a grand piano, for example, the una corda pedal shifts the action so the hammers strike fewer strings, producing a gentler tone. In an upright piano, it moves the hammers closer to the strings, reducing their impact. 

Some upright pianos also feature a practice pedal, which lowers a felt strip between the hammers and strings. This significantly dampens the volume, making it ideal for quiet practice sessions. 

How does a digital piano work?

Understanding the basics of how an acoustic piano works will help you grasp the technology of a digital piano. In short, a digital piano’s job is to replicate the workings and sound of its acoustic counterparts, and it uses sensors and sampling or modelling techniques to achieve this.

Sensors

A digital piano uses sensors to detect how each key is played. Instead of hammers striking strings, the sensors measure the force and speed of your keystrokes, converting them into digital signals. These signals then trigger high-quality recorded samples or computer-generated sounds, replicating the response of an acoustic piano. 

Advanced digital pianos feature multiple sensors per key to capture the small variations in touch, allowing for more control over volume and tone. Some models also include escapement simulation to mimic the feel of an acoustic piano’s mechanism. Since digital pianos do not have physical strings, they rely on built-in speakers or headphones to produce sound.

Hybrid pianos use a natural mechanism for the playing action combined with a sensor. An example of this is the  Casio GP510 Grand Hybrid Digital Piano. This particular model uses the Natural Grand Hammer mechanism and Casio sensors and is the result of a collaboration between C.Bechstein and Casio.

Sampling or modelling 

Digital pianos generate sound using either sampling or modelling. Sampling involves recording the sound of an acoustic piano at various dynamics and articulations. Each note is captured multiple times to ensure a realistic representation.

High-end digital pianos use sampling, a process that involves layering multiple recordings to replicate the differences of a real instrument. This process requires precise microphone placement and post-processing to create an authentic, expressive sound. 

Modelling, on the other hand, synthesizes sound in real-time. Instead of playing back recorded samples, modelling algorithms simulate how a piano string vibrates, how the soundboard resonates, and how different playing techniques influence the tone. This allows for greater responsiveness and customisation. 

Some digital pianos combine both methods, using samples for a natural tone and modelling for how the tone behaves. This hybrid approach balances authenticity with adaptability, making digital instruments more expressive.

The Kawai CN201 digital piano, for example, samples their flagship Shigeru Kawai SK-EX and utilises Kawai’s progressive harmonic imaging technology to follow the tonal changes and dynamics of your playing.

Innovative digital piano technology

Kawai, Yamaha, and Casio are among the most innovative brands in the digital piano industry, pioneering technology that enhances realism, playability, and expression.

If you’re choosing between these brands, Kawai are known for their wooden key actions and rich harmonic imaging, Yamaha lead in resonance modelling and advanced key mechanics, while Casio focus on intelligent sound processing and hybrid key actions at an accessible price. 

Kawai 

Kawai’s Grand Feel wooden-key actions are designed to replicate the touch of a grand piano.

Unlike standard plastic key actions, the brand use wooden keys with pivot points – similar to those found in acoustic pianos. For example, the Grand Feel III action features long wooden keys, counterweights, and a triple-sensor system, providing greater responsiveness and dynamic control. 

Kawai are also known for their Harmonic Imaging (HI) sound engine, which ensures that each note has depth and resonance.

Using high-resolution sampling and advanced processing, this technology accurately recreates an acoustic piano’s natural overtones and harmonic richness. This is especially noticeable in softer dynamics, where you need those subtle tonal details to shine through. 

Because of such forward-thinking technology, Kawai bridge the gap between digital and acoustic pianos and offer authentic key movement and tone production that allows players to transition seamlessly between digital and acoustic instruments.

Yamaha 

Yamaha have a long history of acoustic and digital piano craftsmanship. Their digital pianos incorporate cutting-edge technology such as Virtual Resonance Modelling (VRM), one of Yamaha’s most well-known features.

Seen in models such as the Yamaha YDP 165, VRM simulates how strings interact and resonate across the instrument by replicating the effects of damper positions, resonance, and pedal behaviour. 

VRM creates a dynamic, organic sound and means that, when you play a Yamaha digital piano, the tone isn’t just a static sample – it changes in response to your playing. 

The Yamaha GrandTouch action, as found in the Yamaha CLP 825, enhances realism by providing a longer pivot point and wooden construction, similar to an acoustic grand. It also includes escapement simulation, which allows for fast key repetition and a lighter feel when pressing keys softly. 

Yamaha developed these technologies to make digital pianos as immersive as possible, particularly for professional musicians and concert pianists looking for a highly responsive instrument. Yamaha’s digital pianos deliver a playing experience that closely resembles a grand piano with touch sensitivity and resonance. 

Casio 

Casio have built a reputation for offering affordability without compromising on innovation. One thing you’ll find in their premium digital pianos is the AiR (Acoustic and Intelligent Resonator) Sound Engine.

Rather than relying solely on samples, AiR incorporates elements of physical modelling, adjusting the sound in real-time based on how the keys are played. This results in a more expressive and dynamic response. 

Casio’s Smart Hybrid Hammer Action is another cutting-edge design. It combines wood and synthetic materials for the keys to enhance durability and replicate the keys of an acoustic, while graded hammer weighting means the lower notes feel heavier and the higher notes feel lighter. 

By blending portability, affordability, and realism, Casio have developed technologies that make high-quality digital pianos more accessible.

Plus, through their hybrid key actions and intelligent sound processing, their offerings strike an excellent balance between playability and price, appealing to a wide range of musicians. 

Acoustic vs. digital pianos – which is right for you? 

Acoustic pianos provide a rich, natural sound and an authentic construction that has been developed over hundreds of years. Their hammers, strings, and soundboard create organic resonance – something digital models can simulate but not fully replicate.

The weighted keys and escapement mechanism offer precise control over dynamics, making acoustic pianos ideal for classical pianists, serious learners, and those who appreciate traditional craftsmanship. 

Digital pianos, on the other hand, are more practical for modern living, offering volume control, headphone connectivity, and a variety of instrument sounds.

We recommend opting for a digital piano with good key weighting and an advanced sound engine, like from one of the brands above. This way, you have the best of both worlds – a close replication of the tone and resonance of an acoustic piano and the convenience of a digital piano. You also don’t need to tune a digital piano or wait for it to “settle” when you install it in your home – another bonus! 

FAQs 

How does a piano make a sound? 

When you press a key on a piano, the felt-covered hammers hit the string, which then sends vibrations through the soundboard, therefore causing the piano to make a sound. Different string lengths and tensions produce various pitches, while the sustain pedal allows notes to resonate longer.  

How does the piano mechanism work? 

The piano mechanism works through a complex system of keys, hammers, dampers, and strings. Pressing a key lifts a hammer, which strikes a string to create sound. The damper lifts to let the string vibrate freely, and when the key is released, the damper stops the vibration. This system enables dynamic control and expression.  

How does a piano play different notes?

An acoustic piano plays different notes by engaging different strings when a key is pressed. Lower notes have longer, thicker strings, while higher notes have shorter, thinner strings.

Final thoughts 

The piano is a wonderful instrument, with a whole range of clever workings. Whether it’s an acoustic piano with hammers or its digital counterpart with triggered samples, the piano is certainly one of the most intriguing instruments. If you’ve been asking the question, “How does a piano work?“, we hope we’ve answered it in as much detail as you need!

For more content, check out these articles:

What Kind of Instrument Is the Piano – String or Percussion? 

Keyboard vs. Piano – Which One Do I Need? 

What Do the Pedals On a Piano Do?