Controller Keyboard actions

If you’re looking for a MIDI controller keyboard, here’s a guide to help you understand what I think are the important features.

I’ve been playing keyboards for over 35 years, and in that time, I’ve tried a lot of different types of key actions. In this post, I’m going to break down why some of them feel great to play, and others don’t.

What Does "Feel" Mean?

When we talk about the "feel" of a keyboard, we’re referring to how it feels to play, plus how it interacts with whatever software or hardware it's controlling. The way these two things work together creates the overall feel of the keyboard.

Types of Key Actions

There are three main types of keyboard action:

1. Unweighted Synth Action
   This feels very light to play, and sometimes gives the impression that you could play very fast on it

2. Semi-Weighted Action
   Similar to the unweighted action but with added weights under the keys to give it a slightly heavier feel, which can offer more control over volume and dynamics, Although this doesn't necessarily mean that its better

3. Hammer Action
   This type mimics the action of a real acoustic piano. Pressing a key sets off a mechanism that causes a "hammer" to move, similar to how it works on a traditional piano. The feel of hammer action can vary depending on the brand, but it’s generally heavier feeling than a semi-weighted action.

Each type has its pros and cons. For example, a hammer action keyboard might be perfect for playing piano sounds but not so good for playing synth or organ lines. It’s all about finding what works best for your needs, and there are things you can look for in each of these types of action that will help get the best out of your playing.

Important Factors in Keyboard Action

Here are the main things that affect how a keyboard feels:

1 - Pivot Point

The pivot point is the spot where the key pivots when you press it. If the pivot point is too close to the back of the key, the key will feel different depending on if you press at the front or the back of the key.
This is important because as soon as you play more than one note, the ends of your fingers will be at different distances between the front and the back of the keys, and if the key responds differently due to that distance, it makes it challenging to play evenly.
Of course if you are happy only playing one note at a time, and you're using a midi controller for input of samples or drum patterns, this might not matter to you at all, but I'm aiming this information more at keyboard players that are playing keyboard sounds!

Here's an example of an acoustic piano action:

The pivot points (red felts) are quite a way behind the back of the key, maybe 6 inches, and perhaps more importantly, the pivot point is in a different place for the black keys than the white keys. This means that if I play at the front of the key vs the back of the key, the pressure I need to use in order to press the key down is very similar, and also the pressure I need to use for the black keys vs the white keys is very similar.

In contrast, here's an action from a synth style midi controller:

The distance from the back of the key to the pivot point much shorter, less than an inch, so it feels really different if I play at the front of the key vs the back of the key. Also the pivot point is the same for the black and white keys, which means they the black keys feel heavier than the shite keys, so I have to exert quite different pressure on the keys to get the same velocity. This can lead to it feeling very un-even to play.

Here's an example of a hammer action midi controller:

The keystick is much shorter than the acoustic piano, but the position of the pivot point is closer to the acoustic piano, maybe 3 inches in this case. But, it's still the same pivot point for the black and white keys, so they will probably feel more different to play than on an acoustic piano.

There are a lot of different manufacturers and they all have their own approaches to solving this problem, and the only way to really tell is to play them and find out if this is going to be an issue for you. It's not a subtle thing.... once you start trying this out you will notice really easily which actions have long keys and which have shorter keys.

Kawai have some midi controllers that effectively have the action of a real acoustic piano inside them. Vidal Piano are also making some incredible midi controllers, but both of these solutions are big and heavy, and if you need something to gig with, sometimes you might want to compromise on the feel in order to be able to actually move the thing! Roland, Yamaha and Nord all make some great controllers (which also happen to be stage pianos), and they all have very different feeling actions - in many regards it’s all a matter of preference.

If you have some nice long keysticks to play with, whats the next thing you need to know? I think it's probably . . .

2 - Keyboard Scanning Rate

Every time you press a key, the keyboard has to measure the time it takes that key to get from the top resting position to the bottom of the keys travel, and in working out the time it took the key to travel that distance, it can work out how hard you hit the key. All that measurement has to happen within about 2 ms, and across all keys, so the keyboard has to constantly scan across all keys really fast to work out which one are being played and how hard.

If the scanning rate is not fast enough, it just cant measure all that information and basically approximates the velocities to some pretty coarse fixed values. It's pretty easy to see this if you record some midi data into a DAW, and look at the velocity values. Keyboards with a low scanning rate will show a small number of "fixed" values of velocity, whereas a fast scanning keyboard should show all 127 possible values.

There is an argument that this doest matter, because a lot of sampled pianos only have a limited number of samples velocities, but I don't agree. Even between the sampled velocities there are often other parameters that change to smooth over the differences between layers, and on modelled instruments, there are no layers, so each velocity does indeed make a different sound. Even on synth sounds, if you have velocity controlling filter cutoff for example, you will start to hear when that filter cutoff is "stepped" by the quantised velocity values coming from the keyboard.

I think this is usually a cost factor in the design of the keyboard - faster scanning means more powerful chips which means more manufacturing cost, but it is a very minimal cost increase, and lots of manufacturers have worked out how to do this really well now. Novations Impulse controller has a key scanning rate of 10 kHz, which at the time it came out was considerably faster than most other things on the market, and in my experience did a really good job of measuring velocity. I think more manufacturers are moving in that direction now too.

3 - Velocity Curve

There are 2 kinds of velocity curve - the one thats built into the keyboard which tries to match the way the physics of the keyboard works with a meaningful output velocity, and the one that's usually in the software you're controlling. These 2 curves work together to make a controller "feel" a particular way, but in my opinion its the one built into the keyboard controller thats the most important, because its the one that determines how the extreme low and high parts of the dynamic range feel to the player. There's only so much resolution to play with once you start tweaking the velocity curve in software, and so getting it right at the controller level is really important in making the whole system feel good to play. This is something you can only really figure out by playing different controllers yourself and seeing what feels right, but things to watch out for are usually notes that seem to trigger really loudly for sometimes no apparent reason, and also noticing differences between how the black keys respond vs the white keys.

The black key  / white key response is particularly important in controllers with short keysticks, since the only way to equalise the response differences due to the different front to back key pressures needed for the black and white keys is to tweak the built in velocity curve so its slightly different between the black and white notes.

In fact there is also some computer software that allows you to change the curve between the black and white notes, VelPro by springbeats.com. I've used this to pretty good effect with several different midi controllers.

In my experience, I have found it virtually impossible to "fix" bad internal velocity responses with software. You can slightly adjust a hardware curve with software to match your own playing style better, but if there are problems that are within the hardware curve, there's not a lot you can do about it with additional software.

4 - Key return speed

The way the key returns to the up position can also be important. If its too springy without enough damping, the key can bounce when it returns and sometimes even re-trigger a note. This is easy to test for - you just hold a note down with your finger nail holding the front edge, and then release it with a sortof flick so it returns to the up position as fast as possible. The less bounce the better!

5 - key surface texture and shape

There are three main styles of key shape, what I call the synth shape, which is what most synthesizers have, the organ shape, also called waterfall keys, which have a square front and make it easy to play organ style slides, and the piano shape, which is a square fronted shape with a small lip at the front.

Sometimes hammer action keybaords that are trying to emulate an acoustic piano also have a textured surface. This is very much a matter if preference, but sometimes the super glossy finish of a synth keybed can make it tricky to navigate around the keyboard for piano pieces, so some people really like the textured finish.

By understanding these key features, you can make a more informed decision when choosing a MIDI controller keyboard that works for your playing style and needs. Whether you're playing fast synth lines or acoustic piano sounds, the right keyboard action will make a big difference!