80/20 and sound dampening

Hey all,

I’ve been planning to purchase some 80/20 (1010 series) to put my X-Carve in (though I had to cancel my order for now…) but want to get ahead and start building something to enclose in.

I’m using 80/20 because I like the idea of modular and re-usable parts, even with the higher pricing point over building with materials like woods.

I’m curious about 80/20 and sound dampening. I’ve been searching the web but really couldn’t find anything too useful.
I live in an apartment and want to be mindful of my neighbors. I’m not looking to soundproof, just dampen enough so my neighbors only hear maybe like a low hum at best.

I want to build something around 50"x50"x25" and plan to put this in a corner. 2 of the side panels (front and side) will be 1/4" acrylic, and 2 of the other panels will be something heavier (side and back) like 1/4" MDF. I’ll be adding the economy gaskets on each side to reduce sound leaks and vibrations. If necessary, I can add roxul / sound dampening panels on the 2 non-clear sides.

Would this method work and dampen enough while the machine is in operation? Thank you for your input.

Edit: Never wrote my use-case. I’ll be using to cut acrylic and woods with the Makita router. Won’t be working on aluminum until I get a garage.

I built my first enclosure out of 3/4" MDF, and I found that it wasn’t enough. Milling wood could generate up to 95db just outside the box, which was far too loud. To put that into perspective, a typical shop vac is about 85db. I eventually wrapped the enclosure in 3" thick panels filled with insulation material, but even that wasn’t good enough to allow me to run the machine any time of day I wanted.

After that, I did some sound proofing experiments. I discovered that sandwiching a soft material between two planks of MDF or plywood worked best. I concluded that building a box-within-a-box was the way to go. Basically you build an outer enclosure out of 3/4" MDF, and then line the inside of that enclosure with a rubbery material such as Sorbathane, silicone, or foam rubber. Finally, build an inner enclosure that sits on the rubbery inner lining. The exterior panels and the interior panels are, therefore, mechanically isolated. Acoustic vibrations inside the enclosure will be absorbed by the rubber material and converted to heat before it can escape the outer enclosure.

Most professional sound booths are built with this principle. They have double-layer walls with dead space and insulation in-between the two walls, to quote Wikipedia. This is one of the most efficient ways to eliminate acoustic energy transfer.

Sorbothane works best at converting vibration to heat, but it’s expensive. I found that standard foam rubber also works okay. Basically, anything is better than single-layer of material. I have some hard data I can share later tonight which shows attenuation of sound through different material combinations.

Holy moly! 95dB!

First of all, thanks for your detailed response. I’m surprised to hear your 3/4" MDF with 3" panels of insulation didn’t work out as you originally intended. While I’m well aware that the typical “box-in-a-box” solution works great, I thought that was to help better isolate lower frequencies and not the higher ones from a bit and a router. I’m sure more comes to play when blocking higher frequencies with the air gap and second material, but your results don’t lie – wow – what a big improvement from that inner-box.

I’m not looking to soundproof my enclosure, but try to reduce it to about 80 dB. For “sound-proofing,” I definitely don’t think the 80/20 extrusions can achieve the desired result.
I’m wondering if it’s still feasible to use 80/20 for my desired outcome. I’m going with pure guessing here so please correct me if I’m thinking wrong. If I have an enclosed box made from 80/20, I would like the top,1 side, and the door to be made from acrylic. This way, I can enjoy watching it :slight_smile: The acrylic’s job is to reflect the incoming vibrations to the opposing side. The other 2.5ish sides (the back, the side, and 1/2 the bottom) I can cover with something heavier like MDF. I can layer something similar to like MDF -> roxul -> drywall -> acoustic foam to make sure it absorbs the coming and reflected vibrations.

Do you think I’ll have any luck with this kind of mindset? Oh, I know, let me get some huge king-size thick blankets and just cover the darn thing :wink:

[quote=“KennyChang, post:3, topic:28811”]I’m surprised to hear your 3/4" MDF with 3" panels of insulation didn’t work out as you originally intended.
[/quote]

There were some small holes where sound could escape, and most of the top and front of the box were void of insulation. Folks have had success building thick-walled enclosures, but a lot of those enclosures are really built like tanks.

To get down to 80db with single-sheet walls, I think you can do it if you use rubber washers or thick gaskets on every bolt so there is some play, so some energy can be absorbed by the flexible material. Anywhere a panel touches another panel, add a rubber gasket to help avoid transfer to energy and to help keep the walls sealed tight. Cables going into the box should be snaked through a baffle that has a gasket seal on both sides.

Here’s some of that data that I gathered.

The experiment was very simple. I bought a length of PVC pipe and a couple of end caps. I chopped the pipe in half making two roughly 24" long tubes. I mounted a speaker onto one of the end caps and a microphone into the end of the other end cap, and then stuck the end caps on the two tubes. I lined the open ends of the tubes with a ring of Sorbothane to ensure a good seal and ensure that the PVC didn’t rattle against the test material and possibly throw off the results.

Each spectrum below represents the frequencies (x-axis) and relative amplitude (y-axis) of sound through a different material or combination of materials. The range of the x-axis is 0hz to 20,000hz. The decibel levels on the vertical axis aren’t real, they are only relative.

For this experiment, I used a 10 second white noise audioclip downloaded from AudoCheck.net. Each spectrum represents exactly 10 seconds of recorded audio.

Baseline (Pipes abutted to each other, no obstacle between them)

2" Thick Polystyrene

3/4" Plywood

3/4" MDF

3/4" MDF | 1/4" MDF (i.e. A plank of 3/4" MDF with a plank of 1/4" MDF rigidly connected to create a uniform plank of 1" thickness)

3/4" MDF | 1/4" Polyurethane Foam | 1/4" MDF (i.e. This is foam sandwiched between two planks of MDF – Notice how well it eliminated the high frequencies.)

Somewhere, on some hard drive, I have more data than this. I had intended to do a big write up with all kinds of video and stuff, but just never got around to it. Now that I have the experiment set up again, I’m inclined to rerun the tests afresh and finally get it done.

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Ordering the 1000mm X-Carve this week and was thinking about sound proofing as well.

Planning on a dual wall enclosure, and using a new product named “soundskins” (http://soundskinsusa.com/) we already use at work, for sandwiching, as well as reflective absorption (also want a acrylic window for viewing).

What are your plans for dust collection and what have others done when using the suckit on the DWP611 router?

Thanks again for your informative post BrianStone!
Glad to see your well-thought experiment show nice results. I’ll go ahead and follow something similar.

After I purchase 80/20 for the frame, I’ll go ahead and insert HDF/MDF to most of the sides making sure it fits with the .5" requirements. I’ll add TPE gaskets to handle vibration. I’ll then attach rock wool, and then another sheet of MDF or drywall for the inner layer.

I saw some 80/20 working in action; mbellon from Carbide3d forums has a solid enclosure for his nomad, as well as Edward’s S2 from the Shapeoko forums.

We’ll see how my results ends up once I measure everything :slight_smile:

This isn’t the cheapest method but hey you worst hear it run for the most part lol http://www.soundproofing.org/infopages/liquid.htm

I used this stuff before and its fantastic:

I feel should emphasize that these charts don’t accurately show how much sound is being blocked or if it’ll be enough sound isolation for your specific situation. I think we would need to build a set of boxes in various configurations to get realistic data. All that this data is really saying is that one configuration is potentially better than another, relatively speaking.

On that note… I wonder if my router will fit in that tube. I might have to give that a try. Maybe I can get some data that is at least slightly more realistic than this.

GreenGlue mentioned earlier, its purpose is to absorb much of the energy of sound, and best used between two layers of solids (Wood board, Plaster board etc) It does not cure fully into a solid/firm mass, it remains flexible.

One of the most efficient ways to reduce sound pressure level (SPL) in general is to have a sandwich with soft material and/or air in the middle.

Car aduio guys often use bitumen (asphalt goo) with a thin layer of aluminium (1/16"-1/32") on top.

Also, controlling the SPL coming out of holes/openings goes a long way, google noise traps. Many DIY-able ways to accomplish that.

One of the most important things however it so mechanically isolate the CNC structure from the desk/floor it rest on, any vibrations here can travel great distances in solid materials like wood/concrete.

Check this out. Thick enclosure walls filled with old towels?

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Panels like these cover only a narrow freq. spectrum - however not useless by any means. They will most likely take off some of the higher pitched sounds within the room the carve is used in. They will bypass most of the lower frequencies (cutoff point determined by material and thickness.

Main objective for this type of panels is attenuation of 1. point sound relfection in audio systems/listening rooms - and designed properly they perform very well. I have several of these but used glass wool insulation instead of towels used for this purpose.

Any material with mass used in combination with a porus sustance will affect sound transmission, it is easy and cheap to experiment with :slight_smile:

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