How Our Magnet Action Works

By Tom Rudnitsky Tom Rudnitsky is a co-founder of Vidal and designer of the Magnet Action MIDI Controller.

Jul 28, 2023

Pre-orders are almost sold out. The first batch will close on Monday 8/7 at 11:59pm EST.

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The keyboard landscape today is bleak. There have been no new innovations for the past 20 years, and today's MIDI controllers and digital pianos feel more like bloated tech peripherals than real instruments.

At Vidal, we want to change that. We design and make keyboard instruments that capture the magic of playing a real piano. Using our extensive experience in piano rebuilding (the LA Times featured a short documentary about co-founder Tom Rudnitsky's work), we're bringing the craft of making real instruments back to digital keyboards.

Our first product is our Magnet Action MIDI Controller. It's designed for use both in studios by composers, producers, sound designers, and songwriters, and also for musicians in live settings gigging and touring. In this article we'll be diving deep into how it works. If you'd like to read more about why we started Vidal, click here. Otherwise, we'll get right into it.

Real, Authentic Materials

The first and most obvious choice in our design process was to use real materials wherever possible. Acoustic pianos are incredible works of wood engineering, so wood was a natural choice for the both the aesthetic and functional components of our keyboard. Using modern CNC machines, we're able to achieve incredibly consistent results and tight tolerances across all parts.

For the keys we use quartersawn white spruce sourced from a third-generation piano supplier in Quebec. White spruce is the same material that’s been used for two centuries in making piano soundboards and keys. It's lightweight, strong, and plentiful.

For the case, we chose ash and walnut, two durable and beautiful hardwoods. We source these from a local hardwood supplier who in turn sources from local sustainably-managed Pennsylvania forests. 

Our keybed is made from strong 3/4” furniture-grade plywood, and we’ve reinforced it with oak and hard maple rails to add rigidity.

Measuring the feel of a grand piano

The most important part of the design process of our keyboard was getting the right feel for the keys. We knew it wouldn’t be wise to try to literally recreate the feel of a grand piano down to the last detail, since doing so would mean we’d end up building an entire acoustic piano action itself. This would have resulted in a keyboard that was heavy, impractical to use in most setups, and prohibitively expensive (think a Fender Rhodes, but more complex).

Instead, we sought to discover the essential components that gave a piano action its characteristic feel, and then implement those components in our own compact design. Central to this process was gaining a deeper understanding of the weight and inertia of the keys, which piano technicians refer to as touchweight.

Most manufacturers only measure the touchweight of their weighted keybeds in a single static measurement called downweight. Downweight is a measure of how much force it takes to start a key moving downward. Below we’ve graphed the downweight of a few representative weighted keybeds, as well as our own Magnet Action MIDI Controller and a Steinway Model B for reference.

Measured this way, pretty much all pianos and weighted keyboards seem the same, clocking in a downweight of about 50g. The problem with measuring keys at a single point in time like this is that piano keys are not static. They move, and the feeling of resistance changes across the keystroke. When we graph the response of weighted keys across time, we get a more complete picture of how a keyboard feels.

Here we can see that despite seeming the same at the outset, there are big differences in the touchweight responses of different keyboards across time. When viewed this way, our two representative weighted keyboard actions, the Yamaha P-45 and the Kawai VPC1, both have a significant problem: while the start of the touchweight curve looks good, the weight of the keys remains high at the end of the keystroke, making the keys significantly heavier and more difficult to play. This is a major reason why digital pianos often feel heavy, even though the downweight measurements are correct.

This final portion of the touchweight curve is called upweight, and refers to how much force it takes to hold a key down after playing. On a grand piano such as a Steinway B, the key disengages from the hammer after the hammer hits the strings, resulting in a drop in touchweight.

On grand pianos, upweight typically measures 10g - 20g less than downweight. This means that a piano with 50g downweight will typically have 30g - 40g upweight, depending on the design. Second only to inertia, upweight is a key defining characteristic of a piano action. Sadly, this component of touchweight is overlooked today in all but the most expensive $10,000+ digital pianos.

Our Magnet Action

To create this crucial upweight differential, we designed our own action with magnets in the keybed and adjustable steel screws in the keys. When a key comes close to the bottom of its keystroke, the magnet engages and adds a slight bit of pull to the key, making it easier to hold the key down after keydip.

This design mimics the upweight portion of the touchweight curve on a grand piano, creating a more realistic and comfortable playing experience. This means that technique built on acoustic pianos will transfer more readily to our Magnet Action keyboard, and playing it will feel more akin playing an acoustic piano than on other digital keyboards.

Key Length and Leverage

To create the right feeling of inertia, our action has steel counterweights at the front of the keys and adjustable springs at the rear. The springs create resistance, and the counterweights modify the response of the springs to give the keys the feeling of inertia.

Folding the leverage back on itself like this allows us to create more inertia in a smaller footprint. It also allows us to have the longest balance length of any digital piano or keyboard, matching the length on the keys of a Steinway Model D.

This increased balance rail distance makes it easy to play at all positions on the key, just like on a grand piano. All other digital pianos, keyboards, and MIDI controllers have a far shorter balance rail distance, making it difficult (or even impossible) to utilize the entire length of the key when playing.

Fully Adjustable Touchweight

No matter how precisely the components of an acoustic piano are manufactured, they still need a human touch during the assembly process. This process is called regulation, and can take anywhere from a few hours to a few days on a grand piano. In skilled hands, these adjustments create a consistent response across all the keys, essential for a fluid and satisfying playing experience.

With our Magnet Action MIDI Controller, we’ve designed all aspects of touchweight to be fully adjustable, including the resistance of the springs, the force of the magnets, the height of the keys, and the timing of the MIDI sensors. As part of our assembly process, we spend time dialing in all of these adjustments to create an exact response from key to key.

We ship each keyboard with a standard regulation that we think most closely matches the feel of a grand piano, but the touchweight is fully customizable within +/- 20g. The upweight can also be adjusted via the magnet screws, giving even more precise control over the feel of the action.

For those who want to customize the feel of the keys to match their own playing style, we’ll be offering tools and tutorial videos when orders start shipping this fall. Adjusting the touchweight takes about an hour and is easier than putting new strings on a guitar.

Realistic Haptic Feedback

Feedback is central to the experience of playing an instrument, and for pianos, one of the most crucial components of feedback is hearing the sound of a note at the same time that you feel the key hit the bottom of its keystroke.

On nearly all digital pianos and keyboards today, this feedback is misaligned. Sound is triggered before your finger stops moving. When this feedback is off by even a few milliseconds, it disrupts cognitive feedback cycles in creative activities like composition and improvisation. Our brains can tell that something is off, and although we can’t put our finger on exactly what is wrong, this mis-alignment inhibits immersion in the experience. This mismatch between aural and tactile feedback is a major reason why even high-end digital pianos just don’t quite feel right.

In our Magnet Action, the MIDI sensors are precisely adjusted during assembly so that the feel of a key hitting the bottom of the keybed aligns precisely with a sound being triggered by MIDI data. When these two elements of feedback are aligned, the entire playing experience opens up in a new way. These micro cycles of feedback build and compound into a cognitive rhythm that allows the player to enter a flow state. At a core level, this feedback cycle is why playing an acoustic piano is so satisfying. We like the instantaneous feedback; you push a key, and you hear a note. Even a few milliseconds delay in alignment is enough to disrupt this cycle.

Fast Repetition through Memory Foam

To speed up repetition, we’ve implemented viscoelastic foam (memory foam) that cushions the key at the bottom and top of the keystroke. This foam takes kinetic energy and converts it into heat, quickly stopping the key and allowing it to return to rest without excessive bouncing. This enables fast repetition when playing repeated notes, since the key returns to its at-rest position more quickly. It also dampens energy at the bottom of the key stroke, preventing loud action noises.

High-Resolution MIDI Sensors

To capture MIDI data from the keyboard, we’ve designed and implemented a conductive silicone sensor system, the standard for nearly all keyboards and digital pianos. These sensors have two conductive pads that make contact with a printed circuit board (PCB). The rear pad hits first, followed by the front pad. The difference in timing between these two events tells us how fast a key was moving, and we use this data to send MIDI velocity signals.

Besides sending standard MIDI ON and OFF messages, we also send velocity data for the OFF message, and natively send Hi-Res MIDI data for those applications which can support it. Together, these features can be utilized by piano software like Pianoteq or Keyscape to add more nuance to performances.

Repairability and Longevity

The adjustability of our action design also makes it simple to make repairs. Rather than taking the keyboard to a specialty repair shop, or taking apart the entire keyboard to install a new part, most problems can be solved by simply opening the lid and making a quick adjustment.

For players who are comfortable getting hands-on to fix damage and replace worn components, we’ll offer a complete set of replacement parts available for purchase on our website, including keys, knobs, connectors, electronics, felt, and more.

Our workshop will also be open for repairs, and you can ship your keyboard back to us using the box it originally came in for a quick-turnaround fix.


We started this project out of our own desire to make a more meaningful keyboard instrument for musicians. It's been a labor of love from beginning to end, and we can’t wait to start getting these into people’s hands this fall.

We're keeping the size of our first batch small so we can focus on getting the details right as we build up our production capacity. To place a pre-order, click here. The pre-order window will close on Monday 8/7 at 11:59ppm EST.

Thank you to everyone who's been following along with us on this journey, and to everyone who's placed a pre-order so far! We're humbled by the opportunity to make an instrument that means so much to people, and we couldn't do it without your support. If you have any questions or comments, feel free to send as an email at any time. We're always happy to chat.

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