Sound Proof Room

It looks like you have it figured out for the walls, but don't forget the ceiling and floor...It really comes down to how much money you are willing to spend, as is usually the case...Double sheet rocking with a layer of rubber in the middle is a suggestion...I don't think anything beats several feet of solid concrete lined with lead....A room encircled with a vacuum might though...The decibel level produced as well as the frequencies associated, might yield better results....some methods might be more effective at certain frequencies, like a strong bass vs high pitched non-harmonic noise...It helps to keep the woofer off the floor by at least 6" and setting on a block of styrofoam...

https://www.easytechjunkie.com/how-can-i-make-a-room-soundproof.htm

I always just pump the walls full of mineral wool....

https://www.bobvila.com/articles/best-soundproofing-material/

Rockwool seems to be a popular brand. I see it used frequently in my work environment where areas are sound-proofed for security reasons.

https://www.rockwool.com/north-america/products-and-applications/acoustic-insulation/#products

Rockwool seems to weigh about twice that of fiberglass batts based on my highly calibrated hands.

Do not make the inner walls parallel with the opposite wall. The skew does not have to be much to prevent standing waves.

This is but one of many firms willing to provide products and advice to make a quiet room.

So what are you making; a recording studio, a personal gun range, a panic room, a multimedia room, or just something so your neighbors stop complaining about the weird sounds?

It is a small workshop, that tests small machines that run 24/7. (In my Basement) It isn't really all that loud. Think like the level of sound that say a 1/4-20 nut makes when dropped on a workbench say from a foot high.

This is the next room on the other side of what would be a hallway is a bedroom.

Can you just make a sound deadening enclosure for the machine? We've done this for a compressor that needed to run for a while in an office space.

But why worry about the sound--it serves a purpose. If something goes wrong, you will be able to hear it instead of having it go to destruction--which might have undesirable consequences or even fire. It also reminds me of people who lived next to a RR or busy highway--they would wake up when the noise did NOT occur as expected. The machines would be like white noise, and you would not notice it.

USG Acoustical Assemblies

Sound absorbing screw

It sounds as though a technical chat with those that design and operate both music recording studios and radio broadcast studios is on the cards.

• Of note is that where there is a window between the inside and the outside, the panes of glass or other see-through material are never parallel to each other, thereby obviating the risk of a critical resonance frequency occurring.

"Of note is that where there is a window between the inside and the outside, the panes of glass or other see-through material are never parallel to each other, thereby obviating the risk of a critical resonance frequency occurring."

I did not know this! So double glazing isn't quite parallel? Or only in sound-reduction applications?

This is why discussions with designers and operators of these things is recommended.

True. Out of interest though, double glazing looks parallel & whenever I've installed (or seen installed) secondary glazing I haven't given any thought to whether they're 'too parallel' so just wondering if this was a thing for ordinary applications, say a room with music playing in it.

<...a room with music playing in it...>

If it isn't a broadcast or recording studio than if the windows rattle at a particular frequency when there is a major blasket on the bassy profundo or a tritlly-most on the highest ever reachie then it probably doesn't matter.

To my mind a good approach would be to glue Anechoic foam to the walls and ceiling.

After all it is used to soundproof all manner of rooms and miniature foam panels are used by Cat to soundproof/sound reduce the noise level in earthmoving equipment.

Do you need to soundproof the whole room? Why not build a container specific to needs of the equipment you wish to sound deaden, would be less of a cost burden.

<...a good approach would be to glue Anechoic foam to the walls and ceiling...>

That would certainly reduce the sound inside the room by, typically 6-10dB (been there, done it, secondhand T-shirt now on a well-known internet auction site)..

Whether it reduces the sound permeating to the outside of it is another matter.

As you plan this, make sure you don't do a Great White. If it will burn, then it will usually burn quickly and very hot after you glue it vertically to a wall. With bedrooms nearby, a fast & hot fire would be very bad.

Might be worth contacting

https://eqacoustics.com/

I needed some acoustic foam, and theirs was easily the best value for money, for really good quality foam.

Probably concrete or brick, but that may not be practical. A curtain between the 2 walls might help. The ceiling and floor will contribute. Any heating ducts will be a severe detriment.

https://www.acoustimac.com/soundproofing/sl-mlv-lt100-half-lb?

Drop ceiling tiles are great for making sound proofing and can often be obtained for free from office remodeling job-sites.

They can be cut and stacked in odd and interesting patterns, or layered and stuffed into wall spaces. If they are suspended vertically by wires they will disperse quite a bit of noise. You can paint them, glue them or whatever.

Some pretty good observations and suggestions already.

An interesting characteristic of steel stud wall framing in lieu of wood framing: the apparent STC rating of a wall assembly increases, perhaps by ten points. As redfred pointed out, if a new steel stud wall can be jacked a bit (room not quite square), this will likely help a bit.

Decoupling the drywall from the framing on the sound generation side. Twenty bucks worth of USG resilient channel (RC1), correctly installed, can increase STC rating by about 5 points. Downside to RC1 is wall mounted stuff (e.g. shelving) can negate any gain, plus the channels are a poor support for mounting said stuff.

What! Nobody mentions the big hole in the wall? How about a true STC 64 3” thick sound retardant operable assembly - I have sold and installed several of these monsters, on a contract bid ten years ago they were around $10,000 USD each. Prolly not appropriate here. Firsthand experience, it is amazing how much sound is attenuated by hanging two doors in one frame (one swings in, one swings out). Simple, constructable, obtainable, not a budget-buster. The thicker this wall (thus greater separation dimension of the door faces), the better.

Thumbs-up to whoever said rockwool insulation.

The foamy wall egg crate things will be no contribution to your goal if mounted outside of your acoustic semi-anechoic chamber.

Did you read through the USG brochure posted by norm in #4? Boring and dry, but VERY informative. For even more in-depth technical design criteria, see if you can lay hands on a USG Handbook.

Thanks Everyone.

Lots to digest.

The last statement was was suprised to read like if you have the foam pyramids inside the room, you get Xdb of attenuation. I don't see wht the same amount would happen if you put it on the outside also.

Why not?

Joe

These function to stop reflected sound waves. Outside of your shop there are no objectionable sound waves to reflect.

Reflect/Absorb, either is good for me. Just do not want to hear the sounds that are happening inside the room from being heard outside the room.

Well, go ahead and purchase/install outside if you wish. They won’t hurt your cause, and they do look pretty cool!

Be advised, these are generally dust magnets, a real pain to keep clean.

Keeping clean,,,

Now that's funny, the inside of the room is also a wood cabinetry shop, sawing sanding etc. he he he

Not cleaning up sawdust will make your woodshop an even bigger fire hazard. Because of this, I don't recommend any internal textured surfaces that cannot be easily cleaned regardless of the sound-dampening quality. Speaking of fire hazards, since you apparently intend to have this woodworking machine working unattended an automatic fire suppression and electric power cut-off would probably be a wise idea.

..."As an example, 20 Hz is roughly the low-frequency limit of the human hearing apparatus. This note is so low that its wavelength in air is 17 m (56 ft). If you wanted to deaden a 20-Hz sound wave using conventional noise reduction foams or sound-absorbing walls, you'd need to have something about 4 m (13 ft) thick. The plasmacoustic metalayer system could completely cancel that wave at just one-thousandth of the wavelength in thickness, or 17 mm (0.6 in)."....

https://newatlas.com/technology/ionized-air-noise-reduction/

This is the sound I am trying to suppress. It has some Bass components from when a ball drops to a lower level. But most of the sound is higher pitch when the balls hit each other.

Joe

https://youtu.be/_lkETpEQJRY

Switch to nylon balls...

Nylon Plastic Resin Balls

I actually did that for a while. but because they are soooo light in weight the operation wsn't very reliable.

Did you try to adapt the mechanism to work reliably with the lighter balls?...or just give up straight away?....no judgement, just curious...I understand the 'if it ain't broke don't try to fix it' point of view...

yeah even sleeve bearings/bushings and the movement one time would tilt and then out of the blue next time not

Well you would need to move the fulcrum points slightly to the left...

I'm sure there's a calculation that could be done, knowing the weight of both types of balls and length and weight of balance beams...

True, BUT... then when the first ball enters it tilts and leaves not going in where it should be going.

Plastic balls? Nah, no sale. Would look and sound cheap. A part of the charm of this mechanism is the sound.

Joe, I remember an older thread where you linked the shop page to your family business now turned cottage business. It might be useful and appropriate to share that here, if you also think it can illuminate better the issue at hand.

Well yes you would also have to adjust the height of the pivot point...or possibly the receiver portion, either way, just thinking out loud....If you could make it easily convertible from one to the other with just using a few lever switches, then not only could you run them with plastic or steel balls, you could use the plastic when noise was a problem...an additional stealth mode as it were...like adding complications to a watch, sort'a....You could also add other options, like decorative glass marbles, or polished jasper balls etc etc..

You hardly need a whole soundproof room for that.

Have you tried an inverted terrarium over the clock?

I owned one of those clocks. After several years the tracks wore down so the balls didn't always roll as smoothly as they needed to roll. This clock doesn't make a lot of noise. How does the noise of this clock interfere with the tested machines that run 24/7?

The terrarium will also reduce machine dust from clogging the tracks.

When ya got like a dozen running and in a room like ohhh 10 feet away is someones bedroom,,,, well...

So use a dozen terrariums. They should isolate each acoustic coupling.

What are these clocks placed on? You might have most of your noise coupling into the bedroom by direct mechanical coupling. An antivibration mat under each clock will attenuate that path.

They rest on 3 soft fiberous like feet.

You can get styrofoam coolers for about $1 each...or if money is not an issue, even quieter 1" thick plexiglass.....

Now that has to be the most simplest and might just work idea!

You probably could get cardboard boxes for free, and line them with old quilts or bedspreads you have lying around....

Does this basement workshop share a central HVAC system wirh spaces you are attempting to shield from the sound?

If so, the HVAC ducting likely will become a major path for sound around typical efforts to impede.

Consider removing the ducting to the workspace and installing a ductless HVAC system for your workspace. There are a few ductless HVAC systems packaged and marketed as DIY now.

Lead Sheeting is very good, if you can afford it.

It absorbs almost all frequencies, even better than Styrofoam.

Also the asphalt based sound proofing used on machinery covers and automobiles is good.

Here is a helpful link:https://www.nuclead.com/soundproofing/#:~:text=Lead%20sheet's%20effectiveness%20as%20a,times%20more%20absorbent%20than%20wood.

I don't understand why people are suggesting anything but acoustic foam here:-

https://www.amazon.com/s?k=acoustic+foam&crid=29OGJRJK1HQ73&sprefix=acoustic+foam%2Caps%2C172&ref=nb_sb_noss_1

UP-Date to the sound proofing task.

I got some 3/4" thick Styrofoam and made a cover for the clock. it was on all sides 1" larger than the clock so it was not touching the clock in any way. also I placed the clock itself also on a piece of same styrofoam to try to lessen vibrations into table.

The Result amazed me! If it made any difference at all my ears couldnt tell!

It was just as loud as without the cover! I wonder what would happen if I put those sound proofing foam rubber panels on the stryofoam box cover it in them if that might help?

Seems like your foam is not very dense....or thick...you need one or the other....or both possibly...

I would also expect that to attenuate the sound. Were there any gaps at all where the sound could get out? That is, were all joints, edges, and corners tight with no gaps? Was this rigid styrofoam such as builders use on houses? If so, could it be vibrating in resonance, thus retransmitting the sound?

The foam is lightweight, 3/4" thick, No gaps all glued together. very similar to the styrofoam from like a cooler for camping, picnic, etc.

See my post #49

That's what I am thinking of trying add those to the Styrofoam. can't hurt to try.

Joe

As you say, won’t hurt to try.

Let us consider this: A mechanical stopwatch on a table, ticking away. In an effort to quiet the thing down I cover the device with an inverted styrofoam coffee cup: negligible reduction in sound. Next I use a plastic cup: better, but still a distinct ticking. Now, a drinking glass: better sound reduction than the plastic. Next effort is a coffee mug: Ah, much better! For the finale, invert a mixing bowl over the coffee mug covering the ticking watch. Lift the two covers, add a vibration isolation pad under the sound source, reassemble.

Tah-Dah!

Mass. The foamy triangle thingies are an echo reducer, not a very effective sound reducer. There is a difference.

You could go ahead and caulk the mug tight to the table...

so maybe a "Cover" made from say Drywall material might be better than the Styrofoam. hmmmm?

If mass is the thing, why not try particleboard?

true

The mass of an inverted aquarium/terrarium will be similar to or greater than a particleboard box. Likely a suitable size can be purchased ready for use, no fabrication needed. Also one will be able to see that the clock is still running properly without lifting the lid.

Well, maybe. Be aware the vibration transmitted to the table is a major contributor to the noise.

We are (I am, anyway) operating under a number of assumptions here.

How many clocks might be expected to be test running at the same time?

What is your production cycle today? That is to say, do you build a dozen, then test and calibrate a dozen, then package and ship/store a dozen, then repeat the cycle? Is there a constant flow; cut parts for a dozen, finished parts for a dozen, a dozen being assembled, another dozen in testing... all at the same time?

It seems we went from a 10 meter room with possibly several hundred of these in test stage to covering them individually with beer coolers, aquaria, or evacuated bell jars.

May not be an option but cover with a bell jar & pump the air out.

I like this idea as a test to verify if most of the noise transfer is via the air. I still think most of the noise transfer is direct mechanical coupling to the table (shelf) through the feet of the clock. On that note, the fibrous feet may be compressed flat and not damping any vibrations.

I had that also covered. On the bottom of the clock are 1/4" thick soft fibrous pads.

One at each front corner and one in the center in the rear.

This was placed on the 3/4" thick Styrofoam.

On the bottom of the Styrofoam, was three of the same feet but reversed one in the front and two rear. So any Vibrations from the clock to the desk top has to travel through about 8" of the Styrofoam.

There is one critical thing missing in this hunt to suppress noise, measurement data. Measurements are one of the most important tools for isolating and suppressing noise. Without measurements, you cannot do a methodical improvement and are just hoping to stumble on an acceptable solution.

As for using Styrofoam to absorb acoustic waves, here is some research.

High-end speakers use spiked feet in cups to eliminate unwanted vibrations. Might that be better than spongy feet.

Acoustic foam stuck to the inside of a cardboard box would do it.

It might work, rabbit, it might. I suspect the details of how you, Randall, would attempt to muffle the sound won't match what is actually attempted. No reproducible measurements before or after muffling will be tried, too.

Laymen forget that the perception of loudness is actually a logarithmic response. So reducing the amount of acoustic energy in half will make a barely perceptible reduction in sound. Reducing the acoustic energy tenfold will make something sound half as loud.

Getting the noise this clock makes at 12:59 AM → 1:00 AM from conversation level to whisper quiet library level will mean an acoustic energy reduction of a thousandfold. Some people can be kept awake by a dripping faucet down the hall.

A methodical approach with before and after measurements will identify which methods work best on which frequencies. Trying different ideas and testing only by ear can stumble on a workable configuration but will likely just lead to frustration.

A cheap dense covering for the box would be ceramic tile...I would coat the styrofoam boxes with adhesive grout and cheap odd lot tile you can find on craigslist or other peer to peer sales sites, trying to get the cost below $.50 a sqft..this would fulfill the density requirement and keep the overall weight manageable at the same time....

think so?

Instead of soundproofing, pull a vacuum in it. That way, sound won't be generated.

There has been a lot of discussion about alternate materials for sound attenuation. There must have been testing done to evaluate different materials. Can reports on this testing be found with a search engine?

See post #4 for a pdf of acoustical performance designs. 65 is the highest STC (sound transmission class) and the first example provided is at the bottom of page 17.

You could maybe install a bomb shelter in the backyard, and put all the clinky clanky's in there...

I'm gonna try the 3/4" thick particle board cover next.

Joe

Well an UP-Date.

I tried No cover,

styrofoam cover, perticle board cover, and drywall cover.

NOT a huge amount of differences, check out the video.

Joe

https://youtu.be/nH6pdJsPJEY?si=L64iS2aNqS1W-8r2

Yeah, does not appear to be the sound attenuation we were hoping for.

Agreed, from the video the particle board is the most effective.

Joe, I’ll wager you are tired of these kinds of questions - we are trying to help.

Asking about the PB cover, but applies to all: Are the intersections sealed well? I mean, really gooped up. The cord penetration, is it tight and sealed up? Is the cover isolated from the desk? It (the cover) will resonate/reverberate from the sound energy, and needs to be isolated from the desk - NOT open cell styrene, but EPDM or similar. Lastly, sealing the cover tight to the desk?

Yeah... that sounds like a lot of dinkin’ around to me as well. After all that you will likely see only a few decibel improvement.

Did you try a couple of pillows around and a blanket over the cover? This also seems like a great way to nearly ensure upsetting the clock when uncovering.

The cheapest and easiest way to cancel all the sound you hear might be to buy a set of noise cancelling headphones,and use them.

Here is a link that may help:

Gee!Why didn't I think of that sooner:Use google search.

https://www.lowes.com/n/how-to/how-to-soundproof-a-room