The guitarist strums or plucks the strings, the sax player blows air into a tube, and the drummer whacks the skins with fists and sticks. But keyboard instruments are unique in the music world. Whether plucking a wire, opening a pipe, throwing a felt hammer to strike a string, or activating an electronic circuit, the performer interacts with the keyboard only and has no direct contact with the sound-creating part of the instrument.

In the world of synthesizers, workstations, digital pianos, groove boxes, and controllers, there are a number of keyboard actions available to the modern musician. Let’s take a closer look of some of the more popular — and emerging — keyboard actions.

An interior cross-section showing the hammer action of an acoustic piano, with one of the keys being pressed to show the working mechanism.

The piano hammer action

Pressing a key on a traditional piano throws a hammer which strikes a string to create the sound. Playing the key requires some effort to overcome the initial weight of the hammer. And playing the key with more velocity will cause the hammer to strike the string harder, creating a louder sound. As the player releases the key, the weight of the hammer returning to rest lifts the key back to its original position.

These piano hammers are larger and heavier for the lower keys (which strike thicker and longer strings), and smaller and lighter for the higher keys (which strike thinner and shorter strings).

Today’s digital pianos, workstations, and controllers don’t have physical hammers, but they go to great lengths to accurately replicate the feel and response of a hammer action: a graded hammer action scales the hammer weighting across the length of the keyboard for a more natural feel.

Instead of striking a string, the key makes contact with two sensors. Playing the key with more energy (velocity) shortens the amount of time between the sensors being struck, creating a louder note. The key elements of a pivot point, counterweight, and a natural return can be placed above or below the key, allowing for great variations in the size and shape of the instrument.

The inner workings of a key bed on a digital keyboard with spring action, with one of the keys being pressed to show the working mechanism.

Organ and synthesizer spring actions

With the invention of the electric organ came the spring action. As the name suggests, a mechanical spring is used to pull or push the key back into its original position. The synthesizers and electronic keyboards that followed also use a spring-based action.

Sometimes this is a coil spring attached to the rear edge of the key to pull the key back into position. In other cases, a curved metal leaf spring under the key pushes the key back up.

In comparison to a piano’s hammer action, the spring action offers a lighter touch; the keys do not extend far into the instrument, and the depth of the keystroke is often not as deep. Many piano-trained performers feel more at home on a piano hammer action; and indeed, those actions are ideal for playing piano sounds.

But for the synthesizer player performing blistering runs, phrasing legato solos, or using key dynamics to mix and blend sounds, this lighter and springier touch may be preferred. Organ players crave being able to create their trademark slides, smears, and trills — the types of embellishments that do not come easily to a piano hammer action keyboard.

A closeup of a single key on a digital keyboard with spring action, showing the detail of the spring connection point.

As synthesizers evolved, so did spring-action keyboards.

Keep in mind that unlike the piano, organs did not allow for any dynamic control from the keyboard itself. Organ dynamics were originally controlled by a volume pedal and a percussion circuit that accented notes played in a staccato fashion.

Interestingly, aftertouch — then called Second-Touch, Key Sensor, etc. — was available on synthesizer keyboards first, with velocity-sensitivity following soon after. Once dynamic control and aftertouch were available on the keyboard (and as synthesizers shifted from monophonic instruments to polyphonic) players wanted a keyboard they could approach more aggressively.

Keyboard weighting first involved attaching a metal weight to the undersurface of the key. This extra resistance provided a more solid touch and allowed for more accurate dynamics. The disadvantage of using weights to create a weighted action was — obviously — the extra weight.

Methods have improved, and nowadays, synthesizers with a weighted or semi-weighted action strive to provide a balance between expressive control and portability. Improved “key guides” allow lighter actions to offer even more stability.

A pair of electronic sequencers, the focus of which is specifically on a Korg Electribe with button keys for triggering individual notes, sounds, and patterns.

Button keys and drum pads

The drum machine ushered in a new era of personal production studios and electronic music makers. It quickly became clear that this new generation of players had no attachment to a traditional keyboard. What followed was wave after wave of patter-based instruments that replicated the intuitive programming of a drum machine but also expanded to embrace melodic instruments as well — the Roland Grooveboxes, Korg Electribes, etc.

The descendants of these instruments still use illuminated button keys laid out like a traditional keyboard to aid in programming. More and more, this style of instrument is also seen on stage with DJs and electronic music performers. For many, the button keyboard has provided a portable controller solution to the many on-the-go and laptop musicians seeking the ultimate compact setup.

A side line to the button key is the trigger pad. As computer-based music flourished, performers began to seek out controllers and instruments that used dynamic or static pads to play drum sounds or trigger samples. As the popularity of Ableton Live and other composing software titles grew, so did the need for pad-based controllers. Many controllers today are hybrids, offering a keyboard, pads, and DAW controls in a single package.

The keyboard section of an EMS Synthi AKS analog synthesizer, showcasing its flat metal keybed which allows the performer to incorporate expressive playing techniques.

Flat keys

Flat keys have been around for a while. The Synthi AKS used by Pink Floyd on their landmark Dark Side of the Moon album featured a flat metal keyboard. Many new keyboard controllers — and a handful of exotic instruments — rely on flat metal keys.

Often, these flat keys can measure the position of the fingertip on the key and sense other information to provide a highly expressive performance.

On the other end of the spectrum, the diminutive flat ribbon keyboard (not to be confused with a ribbon controller) has appeared on the Korg Monotron Series and other electronic music instruments. The flat ribbon keyboard provides glissando effects not available on a traditional keyboard.

Keys — the next generation

In recent years, technology and ambition have kept pace, allowing new advances in the arena of keyboard control. For example, Smart Fabric used by the Keith McMillen K-Board adds an extra dimension of control to a low-cost button keyboard.

Keyboard action remains that dramatic interface where player meets machine. In the best case scenario, the keyboard action responds as an extension of the fingers — instantly translating thoughts and intentions into a flawless performance.

There is no “perfect” type of keyboard action. Each player is unique, and each has different needs and expectations. Having an understanding of the different types of keyboard action can help you make wise choices, whether you’re searching for that supreme instrument, adding to your live rig, or fortifying your studio arsenal.

At AMS, we want to help you find your next keyboard, synth, workstation, or controller to suit your musical aspirations. With a team of musicians standing by to answer questions and an industry-leading 45-day return policy, it has never been easier to find your perfect instrument match.