Re: Most of what I've learned about soundproofing

[Guest guest]

"Hi Jarred," says the audience, careful not to speak too suddenly.Wow. Thanks for all that information -- it corresponds to my own research and discussions with the sound insulation vender I've been speaking with -- and is very well written, to boot.My own $10,000 plan (subject to landlord approval -- still waiting) involves the use of isolation clips, which I believe falls into the decoupling category, on our ceiling with two layers of drywall and green glue between. We may or may not put in cotton insulation, depending on whether this would put us over-budget. For the walls, we are planning to just go for another layer of drywall on the existing plaster(?) wall with green glue. We can't afford the isolation clips on the walls, particularly as the original quote for the ceiling alone was $9,000. (The

vender is promising to work within our $10,000 budget for a ceiling and two walls.) In any case, I have yet to have a neighbor who walked on the walls and usually only extreme jerks are a problem in the next door apartments, for which thankfully I have the cooperation of the local police and can use my baseball bat for something less costly. Currently we have great neighbors, but people rarely stay here long.The vender was quite insistent that green glue would do nothing for impact sound from above, which sounds credible to me. What do you think? He also felt it would do nothing for bass, but I feel more skeptical about that for some reason. I mean, I know that bass and footsteps are basically the same category of sound, but nothing?Subject: Most of what I've learned about soundproofingTo: Soundsensitivity Date: Friday, March 2, 2012, 6:01 PM

Hello, my name is Jarred, and I'm a Misophonic ("Hi Jarred", everyone says, pretending like we are all sitting together, rather than over the internet, partly because several of us try to avoid "public"). I have a severe aversion to any sudden sound, no matter how loud or soft, though the loud ones particularly suck, and like the typical Misophonic, I cannot "get used to" the sounds no matter how many times I hear them.

The topic of this massive bastard is soundproofing, which, due to my brand of Misophonia, I've researched quite a lot. Unfortunately, from what I can find, there is NO cheap, easy way to soundproof to the degree that most of us overly sensitive types would prefer, Apart from wearing earbuds [i'm currently using Luxe Microbuds, which are very small (women would love them) and have a decent seal against the ear, which is very important]. Other than that, the only other easy solutions within a moderate price, are lining your house with box fans, or showing up at your neighbors' doorstep with a baseball bat, which could become expensive later. The cheapest decent soundproofing material is basically just regular fire grade 5/8 inch drywall. Beyond that, Soundproofing materials quickly become outrageously expensive.

Residential noise abatement works off of a few basic principles:

1. Add mass. The more dense a material is, the more energy it takes to move it. However, most dense materials are also stiff, and stiff materials vibrate more at the audible level. This is why a solid concrete wall has only a slightly higher STC (sound transmission class) which is a measure of how much sound a material blocks; the higher the number, the better. Limpid (flexible) materials can have a much lower resonance point (the point at which the material vibrates in perfect sync with the sound, causing the sound to be reproduced on the other side of the material as though it were not even there). Ultimately, we want the wall to resonate

below the audible range.

2. Add air gap. As compression waves of matter apply pressure to one side of a wall, the air gap provides a cushion, as it is that air can compress. This causes the wall on the opposite side of the gap to vibrate at a lower frequency. The thicker the air gap, the more the space can compress, and the lower the resonance point will be (at and below the resonance point, the entire wall will behave as a solid mass, which is what we want to avoid). It is important to note here that as the air gap must be completely air tight in order to function as a cushion, it is vital to seal up perimeter edges of all walls, windows, and doors, with acoustic caulking and weather stripping. Be

sure to caulk along where the wallboard meets with the subfloor or hardwood floor; there needs to be a thin gap which will be filled with acoustic caulking.

3. Decouple the structure. "Decouple" is another word for "disconnect"; if something is coupled, it's connected, and decoupled it's disconnected. This is important because if you put a solid material in front of a sound, which fundamentally is just moving waves of expanded and compacted matter, the way for sound to move is for the wave to impact the solid wall, causing it to vibrate, which recreates expansion/compression waves on the other side of it. The goal here, then, is to get the wall on the source side of the noise to vibrate freely from the receiving wall on the other side. Below the resonance point however, since the wall behaves as a solid mass,

decoupling suffers; this is why it is critical to have the resonance below the audible range, not above.

Other than all of that, if you lined your walls with foam, and filled you walls with insulation, the sound is slowed down by friction and increased air pressure as the moving air particles (sound) is forced into the open cells. However, foam on walls will mainly just decrease echo inside the room, which is why it's used in recording studios, and insulation in the walls is limited in effectiveness because the vibrating source wall can simply bypass the insulation by vibrating the studs or joists which it is connected to. This is also a major limiting factor in the air gap principle. Both of these issues can be solved by designating separate structural members for each wall section. In other words, use alternating studs/joists, or double studs/joists. This will also increase the depth of the air gap, plus

allow the addition of more insulation. If a person has some construction experience and/or isn't afraid to do-it-yourself, The materials cost for this superior soundproofing technique are much less than the ultra expensive and much less effective soundproofing materials on the market today.

On the subject, Mass Loaded Vinyl (MLV) is one such expensive product which has been used for several years now to replace lead, as it is much safer. MLV is a wonderful product for blocking out sound; then again so is glass since it too is very dense, yet our windows are horribly ineffective at blocking sound because they are so thin. The problem is, thicker glass costs more money. And though MLV is cheaper than glass per foot, it's not cheaper by much. Beyond this, MLV has a Sound Transmission Class (STC) rating of 26 or so (the higher the better), and an average wood stud wall has an STC of 35 to 40; however, the average sheet of 5/8 inch drywall also has an STC of 28. Not only this, but these STC values are not cumulative; simply doubling the drywall on one side of a wall will only increase the STC by a couple points

due to the fact that the two act side by side as one solid mass. MLV is suppose to work better because it is a limp material with a low resonance point, not to mention that because it is so thin, it does not use up hardly any extra wall space. Even so, there is much controversy, because many people have asked for independent lab testing of MLV, not just by itself, but rather included in a standard wall assembly, which MLV companies have yet to provide. By the way, Acoustiblok is a MLV variant, not some new fangled technology like they like to say.

This same issue holds true for a product referred to commonly as `soundboard'; one of the more popular soundboards is called Homasote. Soundboard was originally an attempt at decoupling a wall: It is a light weight material which one attaches to the studs or joists. Then the drywall is screwed only to the soundboard, not through the soundboard and into the studs/joists. However, this product has had more than enough time to be independently tested, but good luck finding those tests. The unanimous consensus of soundproofing experts everywhere is that soundboard sucks; yet, the product sells because it is cheap, and people don't do their homework. One final point here, is that if you're looking for decoupling, a product called Resilient Channel (RC) has been time and laboratory tested and

is known to work well enough in many cases. A resilient channel is basically a long thin metal strip bent along its width into the shape of an `S'. The RC is attached to the studs/joists and the wallboard is then attached to the RC, which acts as shock absorption to limit the transfer of vibration. A product with even higher votes, accolades, and reliable testing is a newer product which combines hat channel (metal strips bent along their width in the shape of a hat) with vibration damping clips. The clips are attached to every other stud/joist in a 2 foot or so grid pattern, and the hat channel is attached to that. Even so, a double or alternating stud/joist partition has better performance and costs a little less.

I've used the word `damping', to describe the action of canceling out vibration. This is the primary action used by visoelastic damping compounds also used in soundproofing; visoelastic meaning that a substance is both viscous like cold honey, as well as being elastic, meaning that if stretched, it will eventually conform back to its original shape. The most popular brand used is called Greenglue, which comes in caulking tubes and is applied in between 2 layers of wallboard. As was stated before, rigid materials resonate at higher frequencies, limpid materials at lower frequencies. Though the two layers of wallboard act as one mass, the walls will not hold a vibration very well because the compound resists vibration at the frequencies that the rigid materials want to vibrate at. As such, this compound

lowers the resonance of the wallboard, lessens the ability of the wallboard to resonate at all, and converts some of the vibration energy into heat from the internal friction of moving particles of the flexible compound. The product may seem too good to be true, however, it has wonderful STC ratings from independent testers used in various wall assemblies, and is highly recommended by most professionals that I've heard from. Beside which, it really isn't too good to be true, since Greenglue is actually still a little expensive at $12 a tube, and it requires at least 2 tubes per 4x8 sheet of wallboard. A similar product is called Quietglue, and is much cheaper at $9 or so (you'll have to buy a lot of it, and the savings start adding up fast). Lab results show that Quietglue and Greenglue have performance that is too close to call. The good thing about these

products is that, not only are they cheaper products and also have a lot of momentum backing them up, but they are also the easiest to install, can be installed over current drywall, and can also be used after the fact with staggered or double stud/joist assemblies for the best results. One thing I need to clarify is that a decoupled wall works so well with these vibration damping compounds precisely because they both work on different principles. Regardless of what the Greenglue company will say (to make its product seem like the ultimate end-all solution), this product does not `decouple', it only `dampens'. I can prove this with simple deductive reasoning: Resilient channel works as a shock absorber, just like air (though not as good), yet if a careless individual zips his/her screws all the way through the wallboard, through the channel, and into the studwork, the decoupling property (which is

the only property that RC exhibits) is completely ruined. This is the major shortcoming of resilient channel, it's propensity to being improperly installed. You see, the screws rigidly fasten the wallboard to the structural members, shorting the system as though it were an electrical circuit. However, one thing that the Greenglue company touts as a wonderful benefit of its product is the fact that drilling screws through its wallboard/Greenglue/wallboard assembly and into the structural members (which is how you are suppose to attach it anyway) does very little to lower its performance. Rigid fasteners will short any decoupled system, so if it does little to nothing with Greenglue, this shows that the property it exclusively uses is damping. By the way, air decouples many times better than any solid substance because of simple physics. Anywho, that's my

mamma. Like how I just abruptly ended this with no conclusion?

[Guest guest]

We had our house “sound insulated” with all new double or triple paned windows (different thickness of glass and air gaps), as well as adding insulation in our attic because we live near an airport. The excerpt below from what you wrote about the low frequencies is definitely true. Now that the middle and high frequency “screeching” of the jets is not so loud, my son (with misophonia) is bothered even more now by the low frequency vibrations of the jets that still come through the windows and walls. He says it was almost better before when we could still hear the higher screeching sounds because then the low frequency vibrations/sounds didn’t stand out as much. From: Soundsensitivity [mailto:Soundsensitivity ] On Behalf Of whatismisophonaSent: Sunday, March 04, 2012 10:54 PMTo: Soundsensitivity Subject: Re: Most of what I've learned about soundproofing“…Soundproofing for the average person is like trying to find a cure for the common cold, and low frequency is the mother of all noise problems. Consider that really bad low frequency can have wavelengths as big as your room, and have tons of energy backing them up; it's like an invisible wall slamming into yours. Consider STC, which is the gauge of how much a wall will block; the higher the number the better. STC is a measure of medium frequency sounds that usually create most noise problems. However, STC does not include low frequency. . .”

[Guest guest]

will noise-cancelling headphones help block the low frequencies for your

son? Maybe that is something to try.

Jarrod, I hope you will go into the field of acoustical engineering or work at a

soundproofing company. You know so much about it and it would be great to put

that knowledge to practical use.

>

> We had our house " sound insulated " with all new double or triple paned

> windows (different thickness of glass and air gaps), as well as adding

> insulation in our attic because we live near an airport. The excerpt

> below from what you wrote about the low frequencies is definitely true.

> Now that the middle and high frequency " screeching " of the jets is not

> so loud, my son (with misophonia) is bothered even more now by the low

> frequency vibrations of the jets that still come through the windows and

> walls. He says it was almost better before when we could still hear the

> higher screeching sounds because then the low frequency

> vibrations/sounds didn't stand out as much.

>

>

>

> From: Soundsensitivity

> [mailto:Soundsensitivity ] On Behalf Of whatismisophona

> Sent: Sunday, March 04, 2012 10:54 PM

> To: Soundsensitivity

> Subject: Re: Most of what I've learned about

> soundproofing

>

>

> " ...Soundproofing for the average person is like trying to find a cure

> for the common cold, and low frequency is the mother of all noise

> problems. Consider that really bad low frequency can have wavelengths as

> big as your room, and have tons of energy backing them up; it's like an

> invisible wall slamming into yours. Consider STC, which is the gauge of

> how much a wall will block; the higher the number the better. STC is a

> measure of medium frequency sounds that usually create most noise

> problems. However, STC does not include low frequency. . . "

>

[Guest guest]

Peach, thank you for the suggestion. Unfortunately, my son does not like to use any kind of noise cancelling headphones or earbuds because he wants to be able to hear if anything unexpected is happening in the house (or elsewhere). Meanwhile, he mostly isolates himself in his room and plays a homemade version of white noise in there (not through headphones or earbuds). Ironically, I have my own noise cancellation head phones that I wear when he starts pounding on the walls really hard and loud as a way to knock certain trigger sounds out of his head, and I’m not the one with misophonia – it’s just really loud. I have offered them to him for his use and he knows where they are if he ever wants to use them. Also, for low frequencies, I can tell that they seem to help with all frequencies, however my son also “feels” the low frequency vibrations in his chest. The best way he’s found to deal with that is either to play his own white noise really loud, or hum loudly which creates its own offsetting vibration. From: Soundsensitivity [mailto:Soundsensitivity ] On Behalf Of PeachSent: Monday, March 05, 2012 5:00 PMTo: Soundsensitivity Subject: Re: Most of what I've learned about soundproofing will noise-cancelling headphones help block the low frequencies for your son? Maybe that is something to try.Jarrod, I hope you will go into the field of acoustical engineering or work at a soundproofing company. You know so much about it and it would be great to put that knowledge to practical use.>> We had our house " sound insulated " with all new double or triple paned> windows (different thickness of glass and air gaps), as well as adding> insulation in our attic because we live near an airport. The excerpt> below from what you wrote about the low frequencies is definitely true.> Now that the middle and high frequency " screeching " of the jets is not> so loud, my son (with misophonia) is bothered even more now by the low> frequency vibrations of the jets that still come through the windows and> walls. He says it was almost better before when we could still hear the> higher screeching sounds because then the low frequency> vibrations/sounds didn't stand out as much.> > > > From: Soundsensitivity > [mailto:Soundsensitivity ] On Behalf Of whatismisophona> Sent: Sunday, March 04, 2012 10:54 PM> To: Soundsensitivity > Subject: Re: Most of what I've learned about> soundproofing> > > " ...Soundproofing for the average person is like trying to find a cure> for the common cold, and low frequency is the mother of all noise> problems. Consider that really bad low frequency can have wavelengths as> big as your room, and have tons of energy backing them up; it's like an> invisible wall slamming into yours. Consider STC, which is the gauge of> how much a wall will block; the higher the number the better. STC is a> measure of medium frequency sounds that usually create most noise> problems. However, STC does not include low frequency. . . " >

[Guest guest]

Thanks, Jarred, Yes, of course I intend to have the existing ceiling removed and yes, yes, yes, the bulk of the cost is labor. I have not met the actual contractor, so I'm not sure I want that kiss. On the other hand the owner of the company is reasonably cute, so... This is a wood-frame building so I guess that is good news since my chief nemesis is bass beats.Subject: Re: Most of what I've learned about soundproofingTo: Soundsensitivity Date: Sunday, March 4, 2012, 10:53 PM

[Guest guest]

" We had our house " sound insulated " with all new double or triple paned

windows (different thickness of glass and air gaps), as well as adding

insulation in our attic because we live near an airport. " -Cummings

Look up the triple-leaf-effect; it is better to have one continuous air gap than

2 gaps with 3 individual panes. The problem is of course, the best size air gap

for limiting heat exchange in double paned windows is around 5/8 to 3/4 of an

inch; less than that will allow the one pane to pick up more and more heat from

the other, and more than that will create a convective air flow in the air

gap(since you probably don't want to fill the void in between the panes with

insulation). Because of this, the best compromise seems to be one thick layer

of glass on the outside of the house, and a double pane attached to the interior

wall. If you have triple panes installed as one window on the outside of the

house, Attach a layer of plexiglass on the interior side and seal it up well.

You could also buy some materials and create a frame for it and attach it with

hinges and a latch so you can open and close it.

" Now that the middle and high frequency " screeching " of the jets is not

so loud, my son (with misophonia) is bothered even more now by the low

frequency vibrations of the jets that still come through the windows and

walls. He says it was almost better before when we could still hear the

higher screeching sounds because then the low frequency vibrations/sounds didn't

stand out as much. " -Cummings

Mass is particuarly important for low frequency. The easiest solution is to add

more mass with 5/8 drywall plus damping glue. If you already had a window

attached to the interior wall, remove it, then reattach it to the outside of the

new drywall. The more gap you can add, the better. If at all possible, if you

don't have double stud walls and ceilings, that's what you should do. Not to

mention that this would give you one hell of a nice distance between your

outside and inside windows.

[Guest guest]

Thank you for the great suggestions! BTW, to keep it simple I didn’t mention it before, but in some cases I do have two separate sliding windows in one opening, in other words, if I want to open the window, I have to do it twice, one for the inner sliding panes, and again for the outer sliding panes. Another thing I’ve learned is that is doesn’t matter how good your windows or walls are if they are not sealed properly around the framework, because the noise will just come in where there are any leaks at all, the same as if the sound waves were water instead – it would still seep in. That includes where electrical outlets in walls are, too. I’ve been looking at a lot of soundproofing information online and it’s hard to sort it all out, so I really appreciate your condensing all of this information and helping to make sense out of it – thank you! From: Soundsensitivity [mailto:Soundsensitivity ] On Behalf Of whatismisophonaSent: Tuesday, March 06, 2012 11:50 AMTo: Soundsensitivity Subject: Re: Most of what I've learned about soundproofing " We had our house " sound insulated " with all new double or triple panedwindows (different thickness of glass and air gaps), as well as addinginsulation in our attic because we live near an airport. " -CummingsLook up the triple-leaf-effect; it is better to have one continuous air gap than 2 gaps with 3 individual panes. The problem is of course, the best size air gap for limiting heat exchange in double paned windows is around 5/8 to 3/4 of an inch; less than that will allow the one pane to pick up more and more heat from the other, and more than that will create a convective air flow in the air gap(since you probably don't want to fill the void in between the panes with insulation). Because of this, the best compromise seems to be one thick layer of glass on the outside of the house, and a double pane attached to the interior wall. If you have triple panes installed as one window on the outside of the house, Attach a layer of plexiglass on the interior side and seal it up well. You could also buy some materials and create a frame for it and attach it with hinges and a latch so you can open and close it. " Now that the middle and high frequency " screeching " of the jets is notso loud, my son (with misophonia) is bothered even more now by the lowfrequency vibrations of the jets that still come through the windows andwalls. He says it was almost better before when we could still hear thehigher screeching sounds because then the low frequency vibrations/sounds didn't stand out as much. " -CummingsMass is particuarly important for low frequency. The easiest solution is to add more mass with 5/8 drywall plus damping glue. If you already had a window attached to the interior wall, remove it, then reattach it to the outside of the new drywall. The more gap you can add, the better. If at all possible, if you don't have double stud walls and ceilings, that's what you should do. Not to mention that this would give you one hell of a nice distance between your outside and inside windows.

[Guest guest]

" will noise-cancelling headphones help block the low frequencies for your

son? Maybe that is something to try.

Jarrod, I hope you will go into the field of acoustical engineering or work at a

soundproofing company. You know so much about it and it would be great to put

that knowledge to practical use. " -Peach

Active noise-cancelling is not extraordinarily usefull for low frequency, as it

requires a lot of energy. As far as non-electrical noice-canceling by way of

material goes, This may actually make it worse. There's and old technique where

if you want to hear what someone is saying on the other side of a door, you put

the top of an empty glass up against it, and put your ear up to the bottom of

the glass. What this does is raise the resonance within the cavity of the glass

by creating a triple leaf, making sounds more audible.

I noticed the same thing with some cheap construction-type over the ear

headphones. I was actually hearing sounds that I wasnt hearing before! This is

particuarly the case with low frequency. If going with head phones, do your

homework and get expensive ones that are made to deal with this problem.

p.s. Thanks for the compliment it might not be a bad field to go into; I have

been considering it.

[Guest guest]

Regarding your msg: “I noticed the same thing with some cheap construction-type over the ear headphones. I was actually hearing sounds that I wasnt hearing before! This is particuarly the case with low frequency. If going with head phones, do your homework and get expensive ones that are made to deal with this problem”. . . I have seen advertisements for noise-cancellation headphones that are geared for traveling and say they block out the “low drone” of the plane’s engine noise – and those headphones are expensive. I can’t remember which ones those are, but I’m guessing something like that might be what you’re refering to. Thanks, again! Reply to sender | Reply to group | Reply via web post | Start a New Topic Messages in this topic (15) Recent Activity: · New Members 18 Visit Your Group PLEASE BE AWARE THIS IS A STRICTLY CONFIDENTIAL GROUP AND NO MESSAGES ARE TO BE USED FOR ANY PURPOSE OUTSIDE OF THE YAHOO GROUP MEMBERSHIP SITE OR REPRODUCED OR COPIED AND MAILED FOR ANY PURPOSE. ALSO DO NOT SHARE MEMBER EMAIL ADDRESSES OR NAMES WITH ANYONE.Thank you. MJ Switch to: Text-Only, Daily Digest • Unsubscribe • Terms of Use.

[Guest guest]

Thanks for the detailed reply. The information will be valuable to me when I discuss soundproofing with our contractor.