Any Recommendations for Sorbothane Durometer?

What durometer rating of Sorbothane would you recommend for sound dampening in keyboard cases? There’s a big difference between 40a and 70a and I’m curious what you guys have found out with your own experimentation.

1 Like

Since you want the Sorbothane to be under load (squished) by 10-20% for best results, I think the actual sound dampening results are indistinguishable once they’re squished. For me, the duro difference shows up more in the relative ease of working with the material. The higher Duro ratings are easier to cut with a pair of scissors, but a little harder to, say, wedge between a PCB and a plate. Generally, I’ll use 40 or 50.

Im thinking about getting plate and case foams from mkultra . Is sorbothane better, different or how do they compare?

They’re quite different. Sorbothane, as described above, is just for the space between the PCB and the case whereas the mkulta plate foam fits between the plate and the PCB.

The main difference between the case foam of MKultra and using sorbothane would probably be the sound profile and weight. They have their pros and cons in regards to what might work best in different cases. Like @jshufelt said, sorbothane should be under load for best results, whereas the mkulta foam might respond better based off surface area, a different amount of load pressed on to the foam, etc.

simple answer: sound

My last build used 40duro, but I’ve also tried 70. I haven’t been able to tell a difference in the dampening provided by either.

While the biggest benefit to this material is clearly sound and vibration dampening, I also like that it brings some more weight and density to the boards I’ve used it in.

That’s good to know that it works best under compression. It’ll be helpful in choosing what thickness to get.

Mkultra does offer some precut foam for the space inbetween case and pcb too. Im not sure if its meant to be under stress though. If im not mistaken sorbothane is usually 5mm whereas mkultra foam is 4mm

On their website Mkultra says it needs to be squished for the best results. Therefore it is under stress! Mkultra also offers between 2mm up to 5mm depending on which you are getting.

Generally speaking, you’d want a softer material for absorbing sound because it doesn’t transfer vibrations as easily.

I am also looking into getting sorbothane. For me it makes more sense to get sorbothane between PCB and case and a Mkultra foam between PCB and plate so that’s what I’ll be trying out. I also don’t have the patience to cut sorbothane for putting between PCB and plate. lol. Although it should be pretty easy if you place the plate on top of a sorbane and use an exacto knife.


Check out @donpark’s sorbothane strut mod for a good way of getting around having to cut out a sheet of sorbothane for in between the plate & PCB while still getting good sound dampening results!