Sound Proofing

[Perry Winkle]

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.

[Griff]

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

[Clodfobble]

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.

[gvidas]

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.

[Clodfobble]

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.

[Perry Winkle]

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.

[glatt]

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.

[Perry Winkle]

Originally Posted by glatt

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.

[HungLikeJesus]

Maybe you can use sound cancellation technology.

[limey]

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 ...

[footfootfoot]

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.

[Clodfobble]

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

[glatt]

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.

[ZenGum]

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.

[footfootfoot]

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