E7-V2 GML (isolated Gasket-Muted plate-Leaf spring structure)

With new E7-V2 group buying coming up soon, everybody should have already seen the renders of different finishes of this gorgeous board. We’d like to explain more details about what we did for this “never settle” board, regarding the typing feeling improvement and acoustic perfection.

Overall, E7-V2 is using isolated Gasket-Muted plate-Leaf spring structure (we will call it GML below). Following I’ll briefly talk about the motivation, approach, and the goal of GML.

P.S. to get best the sound and typing experience, modding switches is equally important as the structure design of the board. If you don’t care about switch modding, the article may not be for you.

1. Motivation of GML

Since 2019, gasket mounting system is getting more and more popular in the high-end custom keyboard design. At one point, people had belief that there is no good typing feeling if the board is not gasket mount. In reality, due the limitation of the plate material (especially when the plate is stiff), comparing to traditional top/sandwich mount, gasket mount just barely softens the stiff feedback when key strokes on the plate. If you are using very stiff plate like brass plate, the difference is sometimes even hard to notice. However, gasket mount has decent impact on lowering bottom out sound and reducing hollowness of the board, therefore, we believe gasket mount is a mounting system mainly for sound dampening.

How come gasket mount is getting so popular? It should thanks to more and more seamless case design where the top case covers the bottom case. In the past, due to top case is relatively large in the seamless design, the bottom out sound and hollowness produced by top mount is far from clean and crisp typing sound that mainstream keyboard enthusiasts are pursuing. Such high end finish (compare to traditional two halves structure that can easily have color mismatch between two case halves) that these seamless designs gave to everyone, makes much easier to manufacture and QC the case surface finish. That’s why this type of case design is adopted in more and more high end keyboards, where gasket mount also gets its fame over time.

So, how gasket mount really works? Let’s revisit this famous sheet of custom keyboard mounting styles.

Cheat sheet: Custom keyboard mounting styles. 2019.4.7(https://thomasbaart.nl/2019/04/07/cheat-sheet-custom-keyboard-mounting-styles)

From the graph above, gasket mount entirely removes the contact between plate and the top/bottom cases, which prevents the vibration of the sound passing to the whole case via metal medium. Instead, the gaskets absorb the vibration and therefore dampen the sound. But the graph has an issue that most of the gasket mount boards on the market have the same common issue, which we want to address when designing GML structure in our latest E7-V2 board.

2. Approach of GML

2.1 “G”: Issue of traditional gasket mount

First let’s show what the gasket mount looks like in reality

We can notice the gaskets (red in graph) isolate the vertical direction contact between plate and case, but what about horizontal direction?

Without screws to precisely secure the plate, any horizontal movement of the plate would case horizontal direction contact between plate and the case. As a result, we will have two further problems: a. Offset of the plate, where you may have larger gap between keycaps and the case on one side than another; b. It destroys the isolation of gasket mount, where the whole bottom out sound and hollowness problem comes back as the plate contacts the case again.

Regarding how to restrict horizontal direction movement of the plate, most designers did not address it in their gasket mount boards design. Very little amount of designers have solution to solve the issue, and one of them is the designer of Polaris. Gasket mount of Polaris adds several vertical gasket in the inner side of the case, to secure the plate from all directions horizontally. The other designer who just starts to realize this problem is Keycult. Keycult No.2 boards adds some hard plastic alignment pins between the plate and the case to secure the plate horizontally, to avoid the awkward process to align the plate and case during assembling.

As of E7-V2, we will be using the sound dampening foam between the plate and the PCB to address this issue. 

2.2 “M”: Muted plate

With more and more appearance of sound dampening foam between plate and case, people start to customize plate foam for their keyboards even the boards are not designed with it. And last year RAMA U80 even used the plate foam to secure the plate and PCB into the case. With all these adoption of plate foam, its ability to improve typing sound is well recognized now. And we decide to make it even further.

As the graph above, E7-V2 sound dampening plate foam will have extension parts on four horizontal directions (see black parts). With these extension parts counteracting with case, we’ll be able to avoid any possible contact between the plate and the case.

Compare to the solutions by other two designers mentioned above, we believe our approach can largely reduce the interference of this horizontal direction securing process to the vertical direction flexibility of gasket mount.

2.3 “L”: Leaf spring

As a mounting style mainly for sound dampening, gasket mount does not really hit the point of simulating flexibility of plate-less design. Therefore, several designers started looking at solving this issue, and one of the example is Rama Thermal.

From the plate design of Rama Thermal, spring like structure provides excellent flexibility. Similarly, in the E7-V2 plate design, we cut several slots next to the 7 gasket supporting points at top and bottom of the plate, to optimize the pressure on the plate. Because the special form factor of arrow cluster on this 75% board, we need to accurately design the cut slot for each supporting point after iterations of prototyping and measurement. After modeling expert Mr. Calm’s continuous analysis and our team’s various rounds of testing, we finally settled on the current plate design after 17 trials of prototyping.

3.Goal of GML

To summarize everything above, in order to get more consistent front and side profile, E7-V2 uses seamless case design with top case covering bottom case. Therefore, we will use gasket mount to dampen the sound. After finding out existing issue on the horizontal isolation and less than ideal flexibility of traditional gasket mounting style, we designed and adopted GML structure, in order to get fully gasket mount isolation and better flexibility of the plate. With this, users of E7-V2 will be able to experience clean typing sound and vibrant typing feeling.

Last but not least, E7-V2 project has been almost a year since started, and everyone in the team poured into their enthusiasm and contributed their effort. The team really wishes this 75% layout that Exclusive brought up early on could still bring surprise and joy to everyone in this new era of custom keyboard. Hope this post would help you understand the story behind the scene and support us!