Best for sound proofing?

[dave6]

I am not sure I posted this in the right place but here it goes. I need to build a sound restricting enclosure for my Tormach mill. Does anyone know how good plexi glass is for this, thicker, thinner, double pain? The size of the enclosure would be 48" x 76" x 48" high with front access and all sides would be able to slide verticaly up and out for special access. This would also need a top. Any recomendations?

[miljnor]

The high pitch noise coming from most machine tools goes away with just Plain old eggcrate foam.

Just make an enlosure around the machine and then make a little room with the eggcrate stuff. (you don't want chips getting in the foam it would be messy)

if you make the machine encloser sound proof you may have heat issues.

[mxtras]

Another consideration is to NOT make the interior of the enclosure flat-sided - no matter what materials you choose to use.

This is one method that I have personally developed while working to reduce noise levels when dealing with loud machines - if the interior walls are flat and the sound proofing material is less than perfectly effective, the un-dampened frequencies will just be re-directed. Most sound proofing materials are effective on specific frequencies (pitches) at specific angles of incidence. If the walls are "ribbed" or have steps (convoluted) then the sound absorbing materials have more surface area to work with at various angles and the effectiveness of the enclosure system goes way up. I have used this technique on several enclosures for large machines and other equipment such as hydraulic stations with results that impressed the sound consultants that were hired to judge the effectiveness before and after the improvements. Ventilation is a consideration as mentioned. Baffle the venting, too.

Scott

[tobyaxis]

If you have your own shop in your home you could use standard carpeting on the walls and surounding areas. Just make sure you have good ventilation for you and the machine (fire and health hazards etc.). You also want to put shielding/plexy around the machine to prevent chips and coolant from making a mess of the carpeting. I use this method in my garage so the neighbores don't complain at 3am. You never know when a great idea may wake you from a dead sleep.

[Kipper]

Originally Posted by mxtras Baffle the venting, too. Scott

Very important to soundproof the entry and exit points if what you require is silent running...the company I work for produces machines which unenclosed are 120db and when enclosed are 81 (we talk to each other at 50...) so imagine standing at the side of our 35HP machine and not having to raise our voices... the secret is to get the sound to make many turns (bounces) and not get much out of the enclosure. btw our foam is 50mm thick and covers all internal surfaces with no direct ie line of sight holes exiting (not exciting) the enclosure and also to pay attention to whats above and below the noise emanating area. hth...probably wont

[leberen]

Ive seen people ziptie foam around spindle motors ( 1/10 hp) will this prematurely destroy the motor's brushes due to additional heat? What about that sound dampening stuff they use on speakers to prevent rattling in cars, dynomat. Or the diy rhinolining?

[OCNC]

Originally Posted by dave6 I am not sure I posted this in the right place but here it goes. I need to build a sound restricting enclosure for my Tormach mill. Does anyone know how good plexi glass is for this, thicker, thinner, double pain? The size of the enclosure would be 48" x 76" x 48" high with front access and all sides would be able to slide verticaly up and out for special access. This would also need a top. Any recomendations?

There is some good tech info on sound reduction at Soundown .

Chris

[diarmaid]

Sound waves reduce in intensity when they change state from vibration in a solid material (Plexiglass, wood, metal etc) to in a gas (air), and vice versa. The more times the sound waves have to alter state from solid to gas or back again, the weaker they become.
This is why foam structured materials are used for sound proofing (Millions of bubbles of gas surrounded by solid material) . This is also why double glazing is more sound insulated than single glazed (Aside from the vacuum but thats another story!).
Sound waves actually travel better and more efficiently through a solid than a gas, and increasing the thickness of your plexiglass will not make a significant difference to your soundproofing. If you insulate your machine as opposed to your whole room, and want plexiglass windows or doors on the enclosure, consider using more than one layer of thin plexiglass as opposed to a single thick layer to reduce the amount of sound transmission.

Im not sure if you want to spend money but you can buy 2' x 4' soundproof matting at the site below for $20. Also see the 'myths' section before you go to the trouble of installing anything, it mentions the 'egg carton' myth!

http://www.soundproofing.org/index.html

Incidentially, if you dont want to build a double walled enclosure to hold the soundproof matting between, secure the matting on the outside instead of the inside to prevent damage and degredation from dust, chips etc. Once its secured in place on the outside, cover it with something. I haven't tried it but off the top of my head regular kitchen cling-film might be a cheap & easy possibility to keep it clean.

[mung]

Originally Posted by dave6 I am not sure I posted this in the right place but here it goes. I need to build a sound restricting enclosure for my Tormach mill. Does anyone know how good plexi glass is for this, thicker, thinner, double pain? The size of the enclosure would be 48" x 76" x 48" high with front access and all sides would be able to slide verticaly up and out for special access. This would also need a top. Any recomendations?

I have just been looking at soundproofing my mill/lathe and got on to a web site with good information http://soundproofingforum.co.uk/. I phoned and got some really knowledgable person to tell me that probably the most important thing is to make the machine soundproofing enclosure airtight. Followed by decoupling the enclosure by making another enclosure around the first. He also said that double layered plasterboard walls is the cheapest way to make the enclosure as its heavy and and absorbs mass vibration (said the specialist high density plasterboard only made a few % difference to results).

Said if I wanted the cheapest way to do it should just buy standard cheap plasterboard and buy some special acoustic caulking and glue to glue two sheets together and caulk seal all the joints.

Of course seems to me making an airtight enclosure round a large machine is going to be rather impractical for getting access to do any work????????


It looks like my neighbours are not going to be on best relations with me

[GlacialWanderer]

I wrote a blog post about a sound proof box I made for my cnc machine here http://www.glacialwanderer.com/hobbyrobotics/?p=18.

I think the ideas about eggcrate foam and plasterboard would help make it even better. It's already quiet enough, but I might try adding some eggcrate foam someday since that would probably help a lot.

[morgandeo]

Hi friend,
I don't know it's true or false but my friend told me sound proof wall carpet available.He has a carpet shop in our area.

[kostix777]

One of the best sound absorption materials is fiberglass (not the dense, resin glued panels, but the cutton-like fluffy fiberglass). The method by which it works is that when the air vibrations (sound) hit the fiberglass, the fibers in it rub against each other and a lot of this vibrational energy is transformed into small amounts of heat, which "absorbs" the sound.
Say you have 2 parallel walls, be it in your room, or a simple square box, any pair of parallel faced walls, will have an inherent resonant frequency, which happens to be directly related to the wave length of the frequency in question. Lets say we have 2 parallel walls, separated by 5 meters distance.
Now, to calculate the resonant frequency of that parallelity, you need to divide the speed of sound by the separation between the walls.
At 24ºC, speed of sound is approximatelly 344 meters per second, so we have 344 / 5 = 68.8Hz.. this means that when the frequency of 68.8Hz (and its subharmonics and higher harmonic) is played in between those 2 parallel walls, it will bounce between the 2 walls longer than any other frequencies.
Now if we were to damp one of the walls with some layers of fiberglass, when the sound hits that wall, part of the sound will be transformed into heat and part of it will still hit the wall and bounce back (specially the lower frequencies).
This same method can be used to at least partially fix, damp any size resonant system.

Just my little contribution.

Best regards,
Konstantin Tokarev