# I modded my dream MIDI keyboard for DAW use



## funnybear (Sep 2, 2020)

I recently build / modded my own MIDI keyboard for DAW use and wanted to share some notes as many of you have faced the same search for an ideal MIDI keyboard for DAW use.

The main issue is that commercially available controllers basically split into (1) weighted keyboards that try to replicate a real piano action and (2) synth actions that are spring tensed (which includes all the semi-weighted ones). Nothing in between.

For DAW based composers that spend hours a day in front of their DAW, weighted keyboards are too heavy / slow and semi-weighted synth actions to springy and not able to replicate the gravitational physics of a grand piano action.


I literally drove across Europe visiting endless stores to try every single keybed available under the sun. The only one I have not tried yet is the Lachnit based in Vienna (on my list though).

I did not want a synth action "semi-weighted" keyboard that is simply a synth action with some weights glued into each key tensed by a spring, as this does not reflect the physics of weight movement of a real grand piano keybed.

I already have an acoustic piano to write on and needed a midi controller for DAW use that would offer the gravitational physics of a real grand piano action (i.e. where my finger free-floats a weight/hammer moving along a physical joint) but with the following key differences:

much lighter key press weight ideally around 20 to 30 g (the Fatar TP40/L is the lightest available at 75 g)
not weight graded across the keyboard 
maximum key displacement reduced from the usual 10 mm on a grand piano action to around 5 mm

From testing pretty much every currently available MIDI controller, nothing came close to the feel I was after (the Studiologic SL88 Grand was the best of the bunch for me but still a mile off). 

By coincidence I then visited a historic house / museum that had a 18th century early hammer piano on display which the folks at the museum kindly let me try. Similar to this 1772 German square piano:






My jaw dropped and I immediately knew that I found my perfect key action. The keys where light and key displacement short. But most importantly the physics of the key movement was still similar to a modern grand piano. Some more info on the action of square pianos of that time here.

So I decided to take matters into my own hands and mod a midi controller to give me what I wanted. As a dry-run I took a cheap low-end Casio CDP-130 (chosen as the service manual was available for this model - essential for modding) disassembled it and made the following mods:

cut off the main weights of the "hammer weight stem" for each key to reduce key weight - on this picture you can see the original weights on the right and the modded ones on the left:






add layers of hard then soft felt inside the keyboard housing were the key weights bottom out, to (1) reduce the maximum key displacement to about 5 mm and (2) quieten the key action down to a minimum (as key displacement is reduced and key weight is now low, the force at which a key bottoms out is now much lower = low noise)

Here is the modded keyboard built into my desk:






Now I am 90% in heaven  .

Why not 100%? Well, the Casio CDP-130 uses bubble contacts for sensor readings (like 99% of all MIDI controllers - irrespective of action type and quality) which means that consistency of MIDI velocity reading is not ideal. Top MIDI grand actions like the Lachnit or the Yamaha Silent / AvantGrand pianos use laser sensors that are more consistent in reading velocity. But modding those is costly if things go wrong!

My plan is to mod a Fatar TP/40WOOD action next as found in the Studiologic SL88 Grand. That is a bit more complicated as the key weights are not as accessible as on the Casio.


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## d.healey (Sep 2, 2020)

I'd be interested to see a video about this mod


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## funnybear (Sep 2, 2020)

d.healey said:


> I'd be interested to see a video about this mod



You mean how the keys respond when played? I can make a video when I get some time in a couple of weeks (need to create a youtube channel first).

One thing I did not mention in the first post is that I use BOME Midi translator to remap the velocity curve the Casio outputs to create a velocity curve that custom fits the reduced key displacement of the modded keyboard and my personal playing style. It also helps to cover the full range of velocities which are often not output at the bottom and top end of the curve by a lot of keyboards.

But happy to answer questions in the meantime.


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## d.healey (Sep 2, 2020)

funnybear said:


> You mean how the keys respond when played?


That and actually seeing a keyboard being modded. As someone not familiar with how the internals of a keyboard works I think seeing the whole modding process would be useful.


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## pmcrockett (Sep 2, 2020)

This is super interesting. I own a Casio CDP-100, and I'll bet it has the same keybed as the CDP-130. I can't rip it open just yet because it's currently my main MIDI controller, but it would be a good project keyboard if/when I replace it.

I may be misunderstanding how the action works since I've never disassembled a weighted keyboard, but how did you manage to reduce the key displacement without affecting the contact sensors? Does it bottom out 5 mm higher than it used to, or is the resting state of the key now 5 mm lower than it originally was?


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## funnybear (Sep 3, 2020)

d.healey said:


> That and actually seeing a keyboard being modded. As someone not familiar with how the internals of a keyboard works I think seeing the whole modding process would be useful.



Ah I see. In that case let me do a video once I get started with the TP/40WOOD modding and document that.


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## funnybear (Sep 3, 2020)

pmcrockett said:


> I may be misunderstanding how the action works since I've never disassembled a weighted keyboard, but how did you manage to reduce the key displacement without affecting the contact sensors? Does it bottom out 5 mm higher than it used to, or is the resting state of the key now 5 mm lower than it originally was?



Correct: the resting place is now lower then it was before so the total key travel is about 5 to 6 mm until the sensors are triggered.

Here is a schematic of the Casio action (this is the Tri-sensor Scaled Hammer Action Keyboard II which is pretty identical to the CDP-130 except that the CDP-130 only has two sensors).






If you look at the black hammer tip, it will normally bottom out into the top grey square (=felt) once the key is fully depressed.

I cut off the hammer tip half way, so what is left is the metal piece with the oval opening. This now rests on the case bottom where I then mounted felt strips to raise the resting position so the the key is basically always half depressed, giving about 5 mm until the sensors are triggered.

Post modding the keyboard is also no longer weight graded across the keys as the differential weights are at the front of the metal hammer which I cut all off so every key has the same weight.


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## Ashermusic (Sep 3, 2020)

Gee, I don’t know, I use my commercial keyboard and when I want it to feel more like a piano I set it at heaviest and when I want it to feel more like a synth, lightest.

I applaud your industry but I am exhausted just reading about it


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## funnybear (Sep 3, 2020)

Ashermusic said:


> I applaud your industry but I am exhausted just reading about it



 Just wait until I post about my custom made MIDI encoder controller that uses optical encoders as used in robotic joints!


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## Loïc D (Sep 3, 2020)

+1 for video.
That looks like a great project !


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## Curator Chris (Oct 16, 2020)

So I'll be really impressed if someone mods an 18th century square piano into a midi controller.


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