How do you DESIGN a metal keyboard that avoids hollowness?

[PickleTickle]

I feel like some keyboards just stuff foam into the case to avoid the hollowness but I was wondering how people design the keyboard itself to have a nice sound signature without resorting to foam.

[Leslieann]

Ever see a recording studio or the inside of a speaker?
They don't use metal to dampen noise.

More importantly, sound is difficult to predict, it's even worse when it's source comes from 100 different locations. We can sort of predict how it will bounce back to you from inside the case but that's really about the extent of it.

[PickleTickle]

yeah that's fair enough, always wondered if it's just a crapshoot or if there's something people actively choose to do to get certain sounds

[Faceman76]

Ever see a recording studio or the inside of a speaker?
They don't use metal to dampen noise.

More importantly, sound is difficult to predict, it's even worse when it's source comes from 100 different locations. We can sort of predict how it will bounce back to you from inside the case but that's really about the extent of it.

Excellent response. 

I myself prefer baltic birch enclosures, with globs of Acoust-X on the walls, lined with denim insulation, Rockwool or Blackhole 5.  Sealed enclosures get a light stuffing of Acousta-Stuf polyfill.

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[kajahtaa]

Trend now is lust for not feeling your switches or hearing your boards.

Ok. I own headphones tho.

Why design a board at all. Keep a ziplock of atmosphere on your desk and call it a keyboard.

[Volny]

Trend now is lust for not feeling your switches or hearing your boards.

Ok. I own headphones tho.

Why design a board at all. Keep a ziplock of atmosphere on your desk and call it a keyboard.

Just a guess, but I think some people actually use their keyboards to type on and stuff, and consider elements like sound to be secondary, or even distracting. They may even want to build a keyboard that purposely minimises those distractions.

Though each to their own. Some people are less interested in a keyboard's functionality and more in the tactility, sound, and RGB profiles. Fischer Price makes some great boards for those people   

[Leslieann]

Trend now is lust for not feeling your switches or hearing your boards.

I'd disagree with both of those statements.

Yes, many want silent but many want thock and do a lot to achieve it.
Same with feel, many spend insane amounts getting that perfect feel, we wouldn't have nearly the number of tactile offerings if that were the case.

[jamster]

I'm convinced that metal keyboards are a compromised aesthetic affectation to start with. Any "box designed to produce good sound" be it a piano or speakers, will usually be made from wood. Not because it's cheap or easy to work with, but because it is inherently sound dampening. Same with camera tripods, which need to avoid unwanted vibration- the best were (possibly still are) made of wood, then carbon fibre, then metal tubing for the cheapest ones.

Then on top of this are the occasional threads about electric shocks from keyboards. Metal just seems like a material shoehorned into a purpose that it's not fit for.

One standard approach in speaker-land that might work for a metal case is to add mass. Something like Dynamat might work, but you'd probably want to avoid that specific product because it's also covered in a conductive metal foil.

Otherwise, I doubt there's a lot you can do with a metal case. It's not like you can really add internal bracing as the PCB is in the way, or change the dimensions by more than a handful of mm- it's just a long metal box, which is probably the perfect shape for poor acoustic control.

[yui]

Trend now is lust for not feeling your switches or hearing your boards.

I'd disagree with both of those statements.

Yes, many want silent but many want thock and do a lot to achieve it.
Same with feel, many spend insane amounts getting that perfect feel, we wouldn't have nearly the number of tactile offerings if that were the case.

i feel like most peoples that search silence are doing it for the sake of others, like i did when i shared office with someone who was bothered by pretty much any sound, there is the occasional typist that do not like sound but i feel that those are rarer.

i also agree with jamster, metal is used because it looks nice and makes for keyboards that feel really solid, wood would be far better for sound

[Leslieann]

I'm convinced that metal keyboards are a compromised aesthetic affectation to start with. Any "box designed to produce good sound" be it a piano or speakers, will usually be made from wood. Not because it's cheap or easy to work with, but because it is inherently sound dampening. Same with camera tripods, which need to avoid unwanted vibration- the best were (possibly still are) made of wood, then carbon fibre, then metal tubing for the cheapest ones.

Then on top of this are the occasional threads about electric shocks from keyboards. Metal just seems like a material shoehorned into a purpose that it's not fit for.

One standard approach in speaker-land that might work for a metal case is to add mass. Something like Dynamat might work, but you'd probably want to avoid that specific product because it's also covered in a conductive metal foil.

Otherwise, I doubt there's a lot you can do with a metal case. It's not like you can really add internal bracing as the PCB is in the way, or change the dimensions by more than a handful of mm- it's just a long metal box, which is probably the perfect shape for poor acoustic control.

They are to an extent and I've spoken about it many times.
They do stay put better but I think people over emphasize that characteristic, they also can damage desks, don't feel as nice and do have some bad harmonics and electrical issues like you said.

BUT...
Plastic injection molding doesn't lend itself to low volume production, so if you want a low volume design it doesn't make sense to do plastic.
It also carries some interesting sound problems as well as a few other bad traits, it's less porous and reflects higher pitch sound back at you but those are secondary concerns compared to the buy-in cost for a low volume item. You can't spent $80k on tooling and design then only sell 300 of them. Pretty much no one here is going to pay $400 much less $1000 for a plastic TKL or smaller keyboard.

Wood is not a bad idea for sound but keyboards need rigidity and precision and wood is not really good for that. Wood is a living material, it changes based on humidity. On a string based instrument you just adjust the string tension, woodwinds you lengthen or shorten the mouth piece. What do you do on a keyboard that twists and the stabs bind as a result? On tripods carbon fiber is chosen for strength to weight more than any other reason.

That said,
Sound is one of the few things we actually do have SOME control over and it typically plays second or thirds to feel and looks. How many also have a tempered glass pc case? it's no different. Yes, it's a compromise but all of this is a compromise, we're just prioritizing. I have multiple metal and plastic boards, they all have their pros and cons. I love that the plastic ones are so lightweight they can be tossed around and they sound and feel pretty darn good as well, but I also love my aluminum monsters that feel good, stay put, look nice and still sound pretty darn good.

Personally
I would love to build a carbon fiber case with titanium plate just to see how it would compare because you are eliminating so much of the weight, one of metal's biggest "pros" and bypassing the injection mold issue. Unfortunately it's pretty much the worst way to do a keyboard money-wise, it would be stupid expensive.

[Faceman76]

Wood can be very stable depending on the type of wood, how it's cut, and every exterior portion of it must be sealed.  There are also ways to build and design with wood that take into consideration how it may move, hence why the joints on my Victrolas are still tight. 

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[Rico]

Stabilized wood may be the way to go, although infused resin may change its acoustic.

[Leslieann]

Wood can be very stable depending on the type of wood, how it's cut, and every exterior portion of it must be sealed.  There are also ways to build and design with wood that take into consideration how it may move, hence why the joints on my Victrolas are still tight. 

Your Victrola was hand built by craftsmen who personally inspected each (old growth and prepped) piece and decided when and where to use it, the same thing happens on guitars today.

You can't just grab random chunks of wood and toss it into a cnc router and crank out good, precise parts.
Not that it matters, as soon as you move from injection molding to anything cnc the price starts to mimic aluminum and people and manufacturers (rightfully) see metal as more consistent, durable and stable. If you order a batch of 6061 you can bet it's all going to be pretty much the same, it's standardized. Trees, not so much.  And again, sound is one aspect we have more control over so it makes sense to be where the most compromise is going to be made.

Average price of a modest 60% case on Ali Express:
Plastic - $15
Wood - $60
Metal -  $40

[phinix]

... a carbon fiber case with titanium plate ... it would be stupid expensive.

I say let's do it!!!

But that was beautiful description of keyboard build/design and all aspects of what we want, I really liked that post, Leslieann

Myself, I've noticed that after having about maybe 15 different keyboards, I'm not that into aluminium cases anymore.
One of the last keyboards I purchased - kbd67 lite r2, simple ABS mound, with its all design bits, mounting etc make such an amazing sound I love, that I do not want metal case for it.
Now I would like to see TKL keeb like that and I may be done with searching of holy grail for me;)

[Volny]

I'm enjoying reading the insight on this thread.

One thing I will say is that metal doesn't always have to be loud. At least not when it comes to my PC case anyway. I grew tired of how noisy my PC was many years ago, and spent a fortune on the quietest case I could find. It's huge and weighs a ton, mainly because of the relatively thick metal it uses.

I still use it and it's downright silent. As in: the only way I can tell if it's on is by looking at the power LED (when the LED broke once this actually became a problem). I can start to hear it a little only when the GPU is at full load (even back when I had two of them in SLI). Yes I've got noctua fans and a quiet PSU in there, and yes there is foam on the inside of the case. But I'm pretty sure the real hero is just how much solid metal there is blocking everything, and refusing to vibrate no matter what goes on inside.

[9gel]

I don't have an answer to this but maybe I can share what failed.

There's something nice about having a hefty, milled aluminum keyboard. I think dampening shouldn't be completely out of the question. Cars are made of metal, and these days most cars are quiet in the inside. But it took years of trial and error and to engineer the dampening techniques and materials to get to what they are today.

I have a KPRepublic milled alu case with Kailh Speed Orange. I love the heftiness and the speed. What drives me crazy thou is the high pitched clank when the keys rebound and the stab hits the top. It's like someone's constantly banging a spoon on a metal bowl when I type fast.



Adding loose foam underneath the PCB helped slight bit, but the clanking is still there.



I suspect the clanking is due to the aluminum plate, all the rigid attachments via screws passing the vibrations, and not-so-dampened metal surfaces . A few ideas if I have the time to fix this:

- sticking automotive sound deadening material to the inside of the aluminum casing, like Pyle. It worked for my '94 Honda Civic back when I had it
- De-couple the PCB+plate sandwich with the case. This means finding another means of attachment instead of screws
- Sticking foam underneath the plate in between the switch holes. There are a couple of products I've seen. I'll have to get another PCB and plate to do this since I've already soldered all the switches on this one
- Use a non-metal plate

BTW with good rubber feet, metal won't scratch as much.

[kajahtaa]

Has anyone tried 1cm motorcycle seat gel ? Randomly noticed on Amazon