Longmill Enclosure Sound Proofing

Going to purchase a longmill(30x30) this week so I’m getting materials ordered for an enclosure. (acrylic sheets are difficult to find locally these days). I’ve attached a Sketchup of a rough design. I’m going back a forth about this design or an under the table design. I will be putting the machine in my basement storage/workshop room directly under my 3 year old daughters bedroom. Im planning on putting insulation in the floor joists and might even strap/drywall ceiling. I want the inside of the enclosure to be bright as my basement is quite dark, so i’ve ordered some led strip lighting. As for the sound proofing I’m looking into either rigid foam (pink) painted white or the black foam acoustic panels from amazon (which would be dark?). Im also going to use a small shop Vac for dust control but for the time being will just box it in until i can set up some real dust control. Im hoping that someone has had some experience making the machine quite as my two kids do not sleep enough as it is…and my wife would not be happy with me waking them up!

TLDR: Which sound proofing would be better: pink rigid foam board or black acoustic panels.

@BirchcroftDesign Welcome, Skyler.

The black foam acoustic panels are much better at soundproofing than rigid foam.

I don’t get a sense from your pic about how much space you have between your spoil board and the top of your enclosure. If you can’t get to the back, it means that you will be reaching from the front to attach your work piece to the spoil board. You need enough height to do that. I believe you will get tired very quickly of having to squeeze yourself into a low-height enclosure.

Thanks for the info! Never thought of access. I’ll probably make a back or side door for it as my basement shop is quite empty. I have 24" of height for my plan as it makes good use of a 4x8 sheet. Should I go for higher?

@BirchcroftDesign It’s hard to say how high you should go. In terms of the physical equipment, the height will depend somewhat on how you will run your dust collection hose/duct. Where do you plan to run the hose? Even it you run it to the side or down somehow, you still need some height above the topmost part of the dust shoe so that you don’t kink it.

If you use a shop vac, you will quickly find that it is the loudest thing in the room. In my case, I use a 2hp dust collector, as I use it for my other shop machines. When the dust collector is running, I cannot hear the Makita router. When I was using my shop vac, it was much louder than the Long Mill.

I would suggest that you get your table built, then get a cardboard box roughly the dimensions of your planned enclosure. See how you get on leaning into the box to do things like change bits and secure material to the spoil board. Don’t forget that you need to have room for routine maintenance on the Mill - adjusting wheel tension, backlash, etc. For me, I know, 24" would not be enough.

All that said, I am not the best one here to give you advice. (Shut up, then, Grant. :grinning: ) I have no enclosure on my Mill. I don’t hear it in the kitchen - the room immediately up from my basement shop, but I have a suspended acoustic tile ceiling in my shop. I do hear my dust collector. Others here have built enclosures - primarily for dust retention, I think - and they may be able to help you more.

Thanks, all good advice! I’ll definitely do a mock up. Just bought the machine and it looks like 6-8 week wait time? If that’s the case I will have lots of time to get the enclosure squared away…or like most things in my life will be a last minute get it done sorta job…

@BirchcroftDesign Skyler: Keep in mind your x and y dimensions, too. My Mill is on a 48 x 48 bed. That does not give enough room in x to mount the controller on the surface of the bed. I added a small shelf to the left side of the table and mounted the controller to it. I would suggest that you mount the controller outside your enclosure. Even with good dust collection, it’s going to be dusty in the enclosure. There is no sense putting the controller in that environment.

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Yes I had planned on making an auxiliary " control" table off the side. Housing a dedicated laptop, CNC control, dust and light control. Id like to be able to sit and work and watch the CNC while I learn. I think I will build the tables and wait for the CNC to arrive to finish the enclosure portion, that way I don’t over look anything. It also has to be a modular assembly as we are planning on moving within the next year…and I’d like to bring everything with me :laughing:
Anyone use castor wheels for their set up? Been looking at 4" lockable ones.

@BirchcroftDesign My table is on 4@4" poly wheels from Lee Valley. The back two are fixed; the front two swivel. All the machines in my shop are on some sort of moving platform. Too many tools, too little space.

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I can second this. I will also say that I’ve had much better results (at least with 1/4" endmills" running at 12000 RPM instead of the higher rates you see. I am cutting mostly plywood and solid wood. At 12,000 RPM with the right feeds and speeds and router noise isn’t unpleasant at all. But the shop vac. Sweet Jesus.

My 5HP Ridgid is better than the 2.5HP Shopvac brand I had but it is still very loud (just not as high pitched and irritating). I build a large MDF enclosure with sound deadening for it and I REALLY dropped the db level (measured with a meter app on my phone as well as my ears) however I have had the overheat cut off kill the shop vac multiple times when it was in the cabinet (presumably not enough air circulation - my exist pathway is at the bottom of the cabine per the design I got from one of the woodworking mags). So unfortunately I’ve ended up running with the door off and my ear defenders on full time. No elegant solution discovered yet. I may move the vac to the furnance room adjacent to the garage at some point, in the hope having it further away makes it more palatable.

What are others doing?


If you’re going to use a shop vac for dust collection you need to use a high end one to minimize the noise and keep the air clean. Something like a Festool or a Fein would be good but get ready for some sticker shock.
If you do drywall the ceiling, consider using resilient channel to minimize sound transfer.
As for your enclosure I would hinge the door at the top and make the other sides easily removable for occasional access from those sides. I might even make the entire enclosure removable for servicing the Longmill.

I almost have everything up and running. Will post my whole set up once it’s 100%. But I have a 4x8 table top, and a 4x4 enclosure that’s 32" high. Side walls are removable and have plexiglass windows. All 5/8 melamine. Mounted in the table top is a router table and underneath I have a 1hp dust collector and dust cyclone in a insulates box. After building the machine and seeing all the extra parts and tools needed I definitely need some storage drawers as well. Excited to get cutting!


The soundproofing you want really means stopping the sound from getting through the walls/top/bottom of your enclosure. That requires mass. Foam of any type lessens sound bounce but doesn’t stop sound. Density of the material matters most and sealing up all the air gaps you can. Sheetrock is quite effective especially in double thickness and economical. MDF is also good.

Hello, Not sure if SONOpan is available in your area, In Ontario Canada it is sold at Home Depot. This is a sound Noise STOP Technology . Line the inside of the box with this and your good to go