Sound Proofing
 

Not exactly the right forum, but good enough I guess...

We're buying a house, and I want to build a blacksmith shop. We will be within the city limits, so I have to keep things within pretty tight parameters.

General sound level must remain below 55 dBs and spikes below 50 dBs. From what I can tell a good anvil will ring at about 85 dBs.

Is it possible and not ridiculously expensive to sound-proof a building to this level?

Any tips on materials?

I'll either be building a stand-alone shop or converting part of my garage, whichever I think can be made suitable more easily.

This sounds awesome! I hope you get some good ideas as I have a drummer who needs containment.

It is most certainly possible. Ridiculously expensive? Oh yes. I can't say exactly how much material you will need to drop it from 85 to 50 decibels, rather than totally silencing it, but nonetheless soundproofing materials are very expensive, as a general rule. You will basically be creating new walls over the existing walls of your structure, panel by panel. The cost is going to depend entirely on the size of your building, but you can look here to get an idea. You'd want the larger flat panel products, not the wedge-foam things.

My understanding of sound is limited. But I think you have a huge advantage in that you're trying to muffle a very particular sound, rather than prevent contamination from a wide range of possible sources. If you were setting up a recording studio, you wouldn't want to hear anything other than the sound you're trying to record, so you need to be able to muffle the high pitched whine of a FBI drone just as well as the thumping bass of a car driving by, or the trucks downshifting on the highway, etc.

Sound conducts through materials differently depending -- and here's where I'm going out onto a limb -- on how the wavelength of the sound interacts with the density and thickness of the material. Blacksmithing, I imagine, falls within a fairly narrow range of tones, which might allow you to tailor your choice of soundproofing material more specifically than someone setting up a recording studio.

That's technically true, but the sheer volume we're talking about trumps all of those things.

Honestly, the more I think about it, it seems the best thing to do might be to line all the walls with cinderblocks first, then see what amount of sound is leaking through. You're just going for reduction, not total silence. True soundproofing equipment would be a waste.

Thanks for the feedback.

Starting with cinder blocks is definitely more doable. If that doesn't block enough sound, then we can go from there.

A sand filled door is probably mandatory, too. I can probably build that.

I'd like windows, but might just have to run a bit of A/C during the summer months. I see venting and duct work transmitting too much sound...

I'm thinking I'll leave a dirt area in the middle of the shop floor. I can dig down a few feet and fill the hole with sand and mount my anvil on top of that. Chain tie-downs will also help deaden the sound.

The belt grinder and drill press shouldn't be too loud.

When will you be using it? It will be a huge difference if it's just on Saturday afternoons, or if it's weekday nights. You might even be able to get away with no soundproofing if you are just an occasional weekend warrior.

Probably Saturdays and Sundays. If I get it to the point that it won't bother anybody, then it'll be daily.

The thing is, the city code says it doesn't matter. 50(55 spikes) dB is the limit. Between 10 pm and 7 pm it's lower, but that's not an issue since I'm in bed by 9.

Maybe you can use sound cancellation technology.

Do egg boxes look like this where you come from? If so you could do worse than line your room with the cratered tray part of them ...

the angle grinder and bench grinders are going to be louder than hell. The sound has to be 50dB outside the building? I expect almost any structure would be quiet enough except at night or 4:00am sunday.

So Perry, do you have photos of some blacksmithing projects you've done? I'd be interested to see.

I was just researching the noise ordinances around here, because there's a pile driver across the street from my office building and it's really really loud. Not sure what the rules are like where you are, but they are so detailed here, they are almost unenforceable. You have to have a certified person using certified equipment, standing at a legally defined location measuring the sound levels in a very specific way. And a lot of activities are exempt from noise regulations. For example, pile drivers.

What I'm trying to say is that you may piss off the neighbors, but getting into legal trouble is probably a lot harder than you might imagine.

Think laterally. It's probably easier to go around and break into all your neighbours' houses while they are asleep and puncture their eardrums with a knitting needle.

That's kind of a corollary to "It's easier to get forgiveness than permission."

On second thoughts it is probably easier to just kill everyone within a quarter mile radius.

You could try lining the walls with carpet or old mattresses. That's what a drummer friend of mine did when he was young and poor.

I always wondered about velcro in tactical situations.

Yeah, this is Montana. The city code is really easy to read.

Apparently they don't even have to measure the noise: "It shall be unlawful for any person to make or cause to be made any excessive or unusually loud noise or any noise measured or unmeasured which either annoys, disturbs, injures or endangers the comfort, repose, health, peace or safety of any person within the limits of the city."

Very broad.

Good idea. Maybe I can engineer a landslide that will destroy the neighborhood but leave my house standing...

I haven't done any yet. This is a brand new hobby. I'll be posting plenty of pictures as I go. I plan to blog the learning experience, too.

I'm going to buy the minimal set of tools and then learn by building out my toolset by hand. The first pictures I post will be of chisels and tongs and other such stuff. It'll probably be a few months before I start posting blades or ornamental stuff.

This is a really cool hobby. I'd be interested to see pictures too, once you get going.

Sound Proofing (Tailpost)
 

Air-tight is sound-tight. If air can escape, sound can escape. So, every sound-proofing solution will include tubes and tubes of caulk applied to every seam.

Sheetrock walls on 2x4 frames are perfect sound-transmitting membranes. Sound frequencies applied to one side will be vibrated off the other side much in the same way as a speaker cone.

The construction of a sound-proof wall that I think would work best is to frame the wall on a 2x12, with supporting studs staggered from one side to the other, so no direct sound bridge passes from one membrane to the other.

The other way to prevent sound from being transmitted by the wall itself is to lower the resonant frequency of the wall to below the audible human hearing range. You can purchase expensive sheets of lead-impregnated vinyl for this purpose.

There are also special clips for hanging sheetrock that bridge the board above the stud, thus deadening sound transmission.
http://www.soundproofing.org/sales/ssp.htm
http://dougaphs.smugmug.com/Do-It-Yo...73_9jBhk-M.jpg

Flint, I've also heard that uneven wall lengths helps and so does having no wall that is a multiple of another.

Thanks for the link, Feet. STC 60 would definitely do the job.

I got advice from a Filipino guy. He said that he built his sound-deadening building so that each wall is two layers of cinder blocks with a three-inch sand-filled space in between.

I can't imagine running power into a building like that, or ventilating smoke or other gases.

Could you fill the walls with teenagers? Apparently their ears take in all sorts of yelling, but all is silent by the time it makes it to the brain.....

Speaking from the recent experience of building a very specialized studio, I would recommend continuing to do all the research you can about soundproofing, but not worry about it until everything else is already set up, or you know for a fact that you have at least one neighbor who is motivated enough to complain and is not deaf, indifferent, or inclined to think that the sound of an anvil hammering is 'quaint.'

It might be simpler to just bake a few apple pies and pay the occasional fine. Or hang some heavy blankets over all your interior walls.

I think uneven walls and egg crates are for recording and not soundproofing

UT's right, the shaped stuff is to stop sound from reverberating inappropriately inside, not to stop it from getting outside. Flat absorption panels are the type of thing you'd be looking for, if you were determined to look in the professional equipment category. But I'm telling you, cinderblocks are the way to go.

Isn't this going to require, like, a giant furnace with bellows? You're going to need more than ventilation, you're going to need a full chimney.

To start it will be a small coal forge with an electric blower. Someday I'll want to upgrade to a larger forge. Either way, it needs a hood and chimney and a separate exhaust fan.

I plan on building my own forge, but here's an example of the size I'm going for initially.

Yeah. I should really just chill out about it.

Best idea I've heard so far.

Honestly, I'd start by putting the forge and anvil outside under a nice shade tree and just working in the back yard. Lots of fresh air, no worries about chimneys or sound proofing. The anvil will ring, but I bet the neighbors won't complain. If it's like every typical weekend around here, they won't hear you over the sound of lawnmowers, weed whackers, and leaf blowers. Meanwhile, you will get a feel for what works for you, and then you will know how you want to set up your shop if you want to come inside.

http://www.iforgeiron.com/topic/1146...ing-deadening/

http://www.metalartistforum.com/maf/...stands-please/

http://www.iforgeiron.com/topic/10263-sand-anvil-stand/

Hello Perry Winkle

I am excited to hear about your project(s)! I have a different approach to sound deadening than you've seen posted so far. If you're principally concerned about the sound of the anvil being struck, why not eliminate or reduce the sound at the source? I would suggest (as have the iron workers in the discussions above) that you make the anvil itself quieter. Just as you could reduce the sound of a bell by damping it with your hand, you could dampen the sound of the anvil by making a sound/vibration absorbing base for it. I imagined a sand base, and indeed one of the designs discussed uses that. But you could also easily add rubber or silicone or dirt or any other kind of material to the base or even along the surface of the anvil. There are suggestions to put large magnets on the anvil or putting a (large) pin through the hole. Anything to disrupt the resonant vibration will help you stop it at the source.

One nice thing about this part of the plan is that you can easily test it without building much of anything. Put your stand out in the yard, apply your test base material and hammer away! No need to build the shop first.

Naturally, there are other sounds from a blacksmithing shop you'll have to consider and all the construction ideas will work for those sources too.

Sound proofing a room
 

To soundproof your room you will need to use a combination of materials.

The following video link is a brief demonstration on blocking sound: Sound proofing Demonstration

To block sound, you can use a mass loaded vinyl called BlockAid. (http://acousticsfirst.com/blockaid-v...nd-barrier.htm) This can be added to structural composites to increase mass without loosing valuable space and can be used in conjunction with resilient channel, isolation hangers and acoustical sealant.

Always be sure to line cavities with insulation. This prevents resonant frequencies from ringing in the cavities and increases the STC (Sound Transmission Loss).

To keep structural noise from transmitting through the structure, be sure to isolate materials using resilient clips or resilient channels. Sound and noise can be transmitted structurally through any materials that touch without some type of resilient material between them.

Once your structure is complete, you can use acoustical treatments within the room to absorb sound and improve the quality of sound in the room. Even though acoustical panels do not block sound, they will help reduce the overall sound pressure in the room, much like the fiberglass batting that is used with the barrier material in the video.

Egg Carton Acoustical Test
 

We actually had egg cartons tested at a certified acoustical lab.

http://acousticsfirst.com/eggc.htm

They do absorb sound, but please consider their flammability if you are going to line your walls with them.

I've read those links. Those are good starting points.

I hadn't though of fixing the anvil to the stand with silicon.

I'm going to be spending almost $6k on just the basic smithing tools. Anything cheap is very welcome.

I was thinking of a base of shredded tires. On top of that a base of sand that rests fully inside the tire box. On top of that a slab of wood/stump to mount the anvil.

I can put cables with twenty pounds of weight over the horn and through the hardy or pritchel(sp?) holes, when I'm not using it.

If I need to go further, I can dig a pit in the yard and fill it with sand.

My only concern is that it won't dampen the ringing much. But I guess it's worth waiting and seeing, since so many others have had great success.

I read this and I have an observation. Why not try (well, really, why not try all of them.... anywhoo) why not try putting the anvil directly on the sand base? I think putting the anvil on the wood gives it a nice firm setting to ring out from. You want as much clingy gooey viscous low-hysteresis contact as you can get. Imagine this: you have a wooden board or block resting on a pile of sand. Knock it with your knuckles. Hear that? Now, take a board or block and pile the sand on it. Now knock the sand with your knuckles. Which knock is louder? You want to stop the ringing/vibrations from the struck anvil as soon as possible and the board will communicate much more of the vibrations than the sand will.

Just my thought experiment so far, I don't actually have an anvil of any seriousness to test this. Please keep us posted!

I think, years past, they put a Oak post, log or what ever about 6 or 8 feet in ground. As to have a solid base. Sound, I don't have a clue.

Seriously (briefly) ...

Put the anvil outside. Make as much noise as you need to.
Then the neighbours can complain, and you can move it into the workshop. Things will have got better. This will give the psychological feeling of improvement and the neigbours will stop complaining, or if they still complain, you can point to how you have made a big effort to improve things.

I have seen managers do this. They know a problem is inevitable, and they have an easy (but not 100% effeective) remedy. Instead of using the remedy straight away, they start as bad as possible, wait for complaints, then deploy the remedy. People will not be happy but will be less likely to keep complaining because things have improved. It is is slimy trick, but it works.

[/serious]

Oh sure, the neighbors will complain when the noise starts, but when their horses suddenly need shod who are they going to call?

That is so incredibly likely it's not even funny. I wasn't planning on learning farrier-specific skills, but that point might be just the reason.

That's a good strategy. I'll add it to my plan.

Hehe, I was assuming a suburban situation, since that's where the neighbors complain about every goddamn last thing.

If you're more rural, and there are fewer neighbors and they all might need metal worked, you have the social engineering option. Knock on their door and say...

"Hey, I'm putting in an anvil and you might hear some banging(1). I'll never be at it before 10am and never after 10pm(2), but if you ever hear it and need me to stop, just give me a call.(3) And by the way, if you need some metal bent, I'm now your guy, and if it only takes a few minutes, no charge.(4)"

(1) This gives them an opportunity to complain right now, and it tells them that if they do want to complain, they should talk to you personally and not to some authority.

(2) Indicating your thoughtful grace: you have considered that it may be annoying, and are taking your own steps to make sure it isn't all that bad.

(3) Psychologists have shown that the ability to control an irritation is more satisfying than actually removing the irritation. If you give them a button they can press to fix their problem, they will not press the button: because merely knowing they control it is enough.

(4) "Yes, you hear noise, but you like it because it's the sound of a resource, and someday it could be in your favor."

gawd i'm so fucking wordy, sorry

fify.

no other improvement possible.

It is suburban. But it's suburban Montana in a city of 30,000 people spread out over 14 square miles. There are 75,000 people in the county, which is 3,500 square miles.

So lots of people own horses here. Even the city dwellers. The ones that don't often own boats or other recreational stuff that might need metal bending.

I will be social engineering as much as possible.

I was thinking of flyers. I'm also going to invite our immediate neighbors to our house-warming party.