Semi-Weighted Vs. Weighted Keys – A Quick Guide to Keyboard Action

Martin Kristiansen

My name is Martin Kristiansen and I’m the founder and chief editor of HomeStudioIdeas.com. I’ve been playing, recording and producing music for the last 10 years.

In the world of digital pianos and keyboards, there are two main types of keys: semi-weighted and weighted. The main difference between the two is the amount of resistance that is felt when pressing the keys.

Weighted keys are going to be heavier than semi-weighted keys. This is because they have extra weight added to them, which gives them a more realistic feel.

Read on to learn more about key weighting!

At a Glance: Semi-Weighted vs. Weighted Keys

Actually, semi-weighted keys fall under the classification of weighted keys. 

Why?

Even if they’re lighter than on fully-weighted keyboards, there are actual weights attached to each key. 

Still, there are some notable differences between semi-weighted keys and fully-weighted keys.

If you’re in a hurry, here is a quick breakdown of the main differences:

Semi-Weighted Keys

Fully-Weighted Keys

But that’s not all.

What Are Weighted Keys?

Digital pianos have come a long way since they were first introduced in the 1980s. One of the most notable advancements is the addition of weighted keys. 

So, what are weighted keys, and what are the benefits?

You see, weighted keys add more resistance to the keystroke, making it feel more like an acoustic piano.

This is beneficial for two reasons: 

1. It allows you to develop the proper technique
2. It will help you develop finger strength. 

With proper technique, you’ll be able to play with more expression and feeling. Additionally, building finger strength is necessary as the transition to acoustic piano will be less of a challenge.

Read our reviews of the best MIDI keyboards with weighted keys here!

Types Of Weighted Keys

Semi-Weighted Keys

First, semi-weighted keys are commonly found on MIDI keyboards and cheap digital pianos.

So what exactly are semi-weighted keys?

They’re a type of key that’s somewhere between fully weighted and unweighted keys. They offer a little more resistance than unweighted keys, but not as much as fully weighted keys.

Furthermore, they combine the spring-loaded mechanism of synth action with the addition of light weights attached underneath each key.

This happy medium between light and heavy keys makes them a good option for those who want a little more weight to their keys without going all the way.

Another benefit of semi-weighted keys is that they offer more playability than fully-weighted ones.

This can be favorable for beginners and kids who haven’t yet developed the finger strength and dexterity required for fully-weighted keys.

On the other hand, if you want to learn to play the piano and develop proper finger strength, you might find that semi-weighted keys don’t offer the same level of control as weighted ones.

Still, they provide a more authentic piano-playing experience than their unweighted counterparts.

Digital Pianos With Semi-Weighted Keys

MIDI-Keyboards With Semi-Weighted Keys:

Hammer Action

In a traditional acoustic piano, the strings are struck by felt-tipped hammers. When you press a key, the associated hammer is lifted and then strikes the string. The resulting vibration is amplified by the piano’s soundboard and produces the note you hear.

A digital piano with hammer action keys tries to recreate this experience as closely as possible. 

Even if there are no strings on a digital piano, their keys are equipped with actual hammers, giving them a more realistic feel.

Graded Hammer Action

Furthermore, the piano’s strings on an acoustic piano are thinner and shorter in the treble register and gradually becomes thicker and longer towards the bass register.

The result?

More pressure is required when playing low notes than when playing high notes.

Graded hammer action keys are designed to mimic this feature. Hence, the keys are weighted so that the lower notes require more pressure to play, while the higher notes are easier to press down.

As you would’ve guessed, this gives you the most realistic and authentic piano-playing experience.

Moreover, every manufacturer utilizes different designs and technologies when developing Graded Hammer Action.

As an example, at the time I’m writing this article, Yamaha keyboards have three different weighted key designs (depending on series):

One of the benefits of graded hammer action keys is that they can help you develop proper finger technique.

Since the keys are weighted progressively, you have to use your fingers as you would on a real piano. This can help you avoid bad habits like playing with too much pressure or using incorrect fingering.

Digital Pianos With Graded Hammer Action

MIDI Keyboards With Graded Hammer Action

So What About “Synth-Action” Keys?

Synth Action keys are unweighted and use springs, rather than weights to push the key up to its “off” position. 

Put simply, the keys are basically an “on/off” switch, that lacks responsiveness to your touch.

Are there any benefits?

Yes!

First, synth-action keys have a faster and lighter feel which can be beneficial for beginners, as it makes learning to play the keyboard much easier.

Furthermore, the improved playability makes them suitable for synthesizers where you’re playing sounds or instruments other than the piano.

However, straight-up piano players may find that an unweighted keyboard lacks the expressiveness of a weighted keyboard.

Which Keyboard Action Is Right For YOU?

As previously mentioned, action refers to how the keys feel when they are pressed. Are they heavy or light on the touch? And how quickly do they respond?

In addition, knowing which key action to choose can be confusing for beginners. Below are a few questions that can help you decide:

If you answered “yes” to at least one question above, you should consider fully-weighted graded hammer action keys.

Why?

First, hammer action keys mimic the feel of an acoustic piano, which will help you develop proper technique from the start.

Simply put, they provide a more realistic feel that emulates an acoustic piano.

This can help students better learn how to play a real traditional piano. Having a good quality piano action is essential if you are to develop a good piano technique.

In addition,

Similar to doing biceps curls in a gym encourages arm strength, the weighted keys help to build up the muscles in your fingers and hands. After a while, you’ll be able to play for longer periods without fatigue.

Finally, playing on a digital piano with hammer action keys offers more expressive opportunities.

Due to the touch sensitivity, you can vary the volume and tone intensity of your notes in a way that feels more natural when playing.

This is particularly helpful for students who are learning to play complex pieces, as it allows them to have greater control over their dynamics.

So when should you consider a semi-weighted keyboard?

Semi-weighted keys or Synth-action keys are ideal when playing keyboard parts that are not piano or electric piano.

Let’s take an example!

It’s much easier to play string lines on an unweighted keyboard. This is because you can play the notes more dynamically without the keys getting “stuck” or locking up.

In addition, unweighted keys are ideal for playing organ and synth sounds (and fast runs in general). The lack of resistance allows you to perform with greater speed and precision.

Conclusion

It is important to consider the pros and cons of semi-weighted vs. weighted keys before making a decision.

Weighted keys will provide a more realistic feel, while semi-weighted keys are lighter and easier to play. Ultimately, the decision comes down to personal preference.