How does an electric piano work? The anatomy of an electric piano

A grand piano is a complicated instrument.

It’s big, unwieldy, and needs significant upkeep. As a result, as technologies advanced throughout the 20th century, the piano was naturally one of the first instruments that manufacturers ‘electrified.’ An electric piano could fit into a small apartment, be taken on the road, and best of all, be a lot cheaper than a full grand piano. Although they were never intended to fully replace grand pianos, electric pianos remain extremely popular in a wide variety of musical genres. In this article, let’s take a look at how these instruments work.

Let’s start by understanding how a traditional grand piano makes sound. According to piano manufacturer Kawai, there can be over 8,000 parts to a piano action. For our purposes, though, it’s enough to understand that when you press a key on a traditional grand piano, you cause a hammer to strike a string. The string vibrates, and this vibration is transferred to the soundboard through the bridge. The soundboard vibrates the air, essentially amplifying the string’s vibration to create the sound we hear.

An electric piano is similar to a traditional grand in how it amplifies a vibration created by hammers and strings. Unlike a grand, however, electric pianos use electromagnetic pickups to amplify the sound instead of a soundboard. There are three main types of electric pianos, differentiated by the element that vibrates to produce the sound.


Some electric pianos actually still sport string and hammer actions much like a traditional grand piano, but feature piezoelectric pickups as a means of amplifying the sound. Perhaps the most notable example of an electric piano that uses strings is the Yamaha CP-70.

Since grand pianos also use strings, playing this kind of electric piano feels the most like playing a traditional instrument. The CP-70 was wildly popular among touring keyboardists since it was easy to mic up and delivered a powerful sound that could keep up with the rest of the instruments on stage. However, tuning this kind of electric piano is tricky – it’s similar to tuning a real piano, which is an art form in and of itself. Throwing it around with the rest of the band’s gear after a show probably didn’t help keep the strings at their perfectly ideal tunings! While a sizable vintage market exists for these instruments, they’re less popular today compared to their tine and reed counterparts.

Here’s what a CP-70 sounds like, emulated using the software instrument available in XLN Audio’s Addictive Keys Complete Collection:


The iconic timbre of many electric pianos is generated by a hammer striking a piece of steel wire, called a tine, that’s attached to a tonebar. The tonebar resonates with the struck wire, acting as an asymmetrical tuning fork. Think of the tuning fork as the counterpart of the vibrating string of a traditional grand piano, and the tonebar as the soundboard-like resonator (except each key has its own tonebar). Each individual fork is tuned using a small spring that adjusts the length of the tine.

Please excuse my amateur playing as you enjoy this tine piano demo, created using the Mark One instrument from Addictive Keys Complete Collection:


Some electric pianos, most notably the Wurlitzer models, use reeds as sound sources. When a key is pressed, a hammer strikes a metal reed, which is amplified via an electrostatic pickup. Perhaps the most idiosyncratic sound of all electric pianos, the reed system makes these instruments capable of producing a wide range of sounds, from soft and sweet to barking and distorted. Although the reeds have an unmistakably beautiful sound, they’re also prone to degradation, as we learned firsthand from working on the Wurlitzer 200A at the Splice studio (pictured below).

Electric pianos with reeds are incredibly difficult to tune. The pitch varies based on the length of the reed, so fine tuning is achieved by adding a specific amount of solder to the tip of the reed to make it the exact / perfect length. This is a finicky business, to put it generously. If stray metal shavings and bits of solder touch things they shouldn’t touch, the piano’s onboard amplifier can short out, causing nasty popping noises and even complete blowouts. These instruments have earned their reputation as divas – but when they’re really singing perfectly, it’s a transcendentally beautiful experience.

Here’s a demo recording of the Wurlitzer from the Splice studio:

Do you have any questions about the anatomy of electric pianos? What instrument do you want to see us explore next? Let us know in the comments below.

Incorporate high-quality electric piano sounds into your own music with XLN Audio’s inspiring software instruments:

January 29, 2021

Max Rewak Max Rewak is a record producer, audio engineer, and music writer, based in New York and currently working in Sounds content at Splice.