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Semi-soundproofing for semi-angry neighbors Effects Pedals, Units & Accessories
Old 16th December 2010
  #1
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Semi-soundproofing for semi-angry neighbors

Hello,

Being new to the forum, I've read through quite a few threads regarding soundproofing, especially when dealing with residential spaces in which sound bleeding into other apartments becomes an issue. The most effective solution seems to involve no less than building a room within a room in order to stop the lowest frequencies, but unfortunately this is not a very feasible option for me, as I am renting an apartment in Brooklyn and will very likely move out when my lease is up in August. It just doesn't make sense to put in the time and money required for thorough soundproofing when I'm picking up and leaving in less than a year, most likely for a place where I will be building a proper studio. However, I've received complaints from neighbors due to the noise levels, as I often hold band rehearsal in my apartment with a live drumset and ample amplification. The walls are SUPER thin, I'm guessing only a single layer of drywall on either side, as I can often hear conversation in neighboring apartments with alarming clarity.

My goal here is not to kill the transmission of sound into neighboring spaces, but only to reduce it, as my neighbors' main objection is the sheer volume bleeding into their space, making our rehearsals sound like they are taking place in their living room. While I plan to attach drywall panels to the sheetrock, I am concerned about the windows in the back wall of the studio providing an easy route for sound transmission despite treatment of the other walls.

A brief explanation of the space may help to illustrate--it is a loft-style apartment, a big open space that is much longer than it is wide. I would say the total dimensions are around 50' x 15', but the studio is all the way in the back, taking up about an 18' x 15' portion and leading into the kitchen, which is about 10' x 15'. The apartment is then somewhat split by the bathroom, which juts out about 7' into the width of the space and is about 7' long, creating a hallway that is filled with several pieces of furniture and a sleeping loft about 7' up (the ceilings are maybe 15' high). After the bathroom, the width of the apartment opens back up to its original 15', where the living room runs about 10' before you hit the front door. I have neighbors on both sides, and their apartments are identical to mine so the two side walls are neighboring walls all the way across and they have the same windows (on the back wall of the apartment) that I do. Thus, sound bleeding out my windows comes right back in through theirs.

Which leads me to my next issue--the back wall includes large, loft-style windows about 10' up. Other than that, the back wall is actually made of brick, so the windows are really my primary concern for that particular wall. I am willing to plug them with appropriate materials but still need accessibility to at least one of the windows. I realize that isolation is only as good as your weakest link, but attaching drywall panels (type X 5/8", to be specific) to the side walls of the studio should cut down on the total SPL bleeding into other apartments even if the windows are not completely soundproofed, should it not? I may even have the budget to apply double layers of drywall panel throughout the studio with green glue in between, but I am also wondering if structural integrity becomes an issue with the same screws going through both of the panels into only the wooden studs in the wall. The panels would probably be 4' x 8' each, going 8' up the wall and 4' across. Might it be beneficial to get taller panels thus covering a greater height up the wall, or would the difference in isolation be negligible?

It is also worth noting that the back corners of the studio, where the brick of the rear wall meets the sheetrock of the side walls, seem to be very susceptible to sound transmission. I can hear conversation next door particularly well through them, maybe even more clearly than through the windows. Perhaps some kind of caulking may be appropriate to address this?

In terms of SPL figures, our rehearsals probably get up to 100-110 dB at the loudest, and I'm guessing the neighbors hear only slightly less than that. Getting the level that they hear down to 60 dB, if not less, seems a reasonable goal. In terms of budget figures, I would like to spend less than $1000.

Any feedback as to the best technique for plugging the windows and the practicality of the drywall/green glue scheme considering leakage through the windows would be greatly appreciated. I apologize if I left out any essential information, but just ask me and I will provide. I can also provide pictures of the space if necessary.

Thanks so much,
Josh
Old 16th December 2010
  #2
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Robo's Avatar
Quote:
I often hold band rehearsal in my apartment with a live drumset and ample amplification
Quote:
our rehearsals probably get up to 100-110 dB
You must be joking!? This is really disrespectful behaviour and is probably even illegal. I don't even know why or how you would feel comfortable having a rehearsal in a place like that with neighbours all around. Any reasonable person in your situation would/should just think 'we can't do this here'.

So my advice is you have to find a more reasonable rehearsal space! Treating a room like that with $1000 is not going to be worth it, the neighbours will still complain.
Old 16th December 2010
  #3
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Well, I can assure you it's illegal, but my neighbors tell me that bands have populated the building before, and I get the feeling it's not the rarest practice in this part of Brooklyn. A lot of musicians live in Bushwick, and I'm sure most of them can't afford a separate studio of their own in a commercial space and can barely afford to rent studio time for rehearsal on a regular basis. Being that there are a lot of converted factory loft spaces in this part of town with lots of open square footage, a DIY studio/apartment is actually a pretty practical solution. If it weren't somewhat acceptable where I live, it's likely my discussions with my neighbors and landlord on the subject would have been much less friendly. We're as courteous as possible, usually rehearsing during the day while most people are at work, and I'm only trying to be more courteous by reducing the noise levels coming from my apartment. We generally rehearse rather quietly too, and only get up to the decibel levels I mentioned on rare occasion (note: 100-110 dB at the loudest)--one such occasion was a concert held here from 10pm until 2am, in which the neighbors were all consulted before hand and did not seem remotely opposed to the idea.

Thank you for your response, but please refrain from hastily judging my level of respect for others and ability for reason when you're not entirely aware of the situation. I posted on this forum seeking assistance in making a convenient situation for musicians in New York that much more convenient by lessening any trouble it might cause others, not to evoke a discussion of my character. I am relatively confident that something can be done to make life easier for both my neighbors and myself, and would be grateful for any advice I may use toward that end.
Old 16th December 2010
  #4
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Robo's Avatar
Ok, fair enough. The way you stated it did sound like you were not really concerned about the neighbours though. With the additional info you provided about discussions with the neighbours it seems it's not such a bad situation.

Cheers
Old 16th December 2010
  #5
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Soundproofing needs lots of mass and a fully sealed room with no route for sound to escape. I think your best bet is to rent a rehearsal room or get electronic drums, amp sims, and headphones for the whole band. Or ask the neighbours when they will be out so you don't disturb them.
Old 16th December 2010
  #6
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fabricaudio's Avatar
 

It is not possible with less than 1000$.

Nikolas
Old 16th December 2010
  #7
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Quote:
Originally Posted by fabricaudio View Post
It is not possible with less than 1000$.

Nikolas
+1
Old 18th December 2010
  #8
Gear Guru
Electonics

Rubber drums, Pods. JamHub or small mixer and headphone amp.
Much easier to hear, much better rehearsals.
DD
Old 18th December 2010
  #9
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jhbrandt's Avatar
Quote:
Originally Posted by DanDan View Post
Rubber drums, Pods. JamHub or small mixer and headphone amp.
Much easier to hear, much better rehearsals.
DD
^
|
Smart man! Excellent Idea. +1

Cheers, John
Old 18th December 2010
  #10
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Quote:
Originally Posted by jhbrandt View Post
^
|
Smart man! Excellent Idea. +1

Cheers, John
True, but i doubt the author will be up for this. Considering he is doing rehersals at 110dB, i think he needs the volume
Old 18th December 2010
  #11
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Rod Gervais's Avatar
 

Quote:
Originally Posted by fabricaudio View Post
It is not possible with less than 1000$.

Nikolas
Absolutely correct - this cannot be done for that............. it might not be possible for 10 times that - and there is the real wrinkle.......

When you want to isolate for absolutely the least amount of money you have to first hire a firm that specializes in acoustic analysis to determine exactly how the sound is traveling into the neighboring property.

They not only check the sound levels in the apartment in general - but also the various components that make up the space in question to determine exactly how much is being transmitted through each of them.

For example - even though the wall (right now) is apparently where the majority of the sound is being passed through (I say this based on your comment that you can easily hear conversations through them) you could well find that even if you add tons of mass to them, once they are no longer the weakest link - the floor is now flanking path that becomes the weakest link (just one example of many possible paths) - and in the end not achieve any more than 10dB (perhaps even less) of an actual increase in isolation with the money you spent beefing up your wall.

Unless you are willing to go the extra mile and do everything you can possibly do in order to isolate your space - your chances of success (by dealing with just a little piece of the potential problems) are not all that great.

In other words - you could invest a couple of grand doing everything you talk about - and (in the end) only deal with maybe 5dB of the frequencies that really matter here...... the problem frequencies - which is to say "the low frequencies".

Cutting out 40dB of Bass and drums is no simple task.

When I speak of the paths into that space (flanking paths) I have a true story that illustrates it well.

In 2006 I was just finishing a major project - which included a high rise hotel. As we rushed through the finishes some of the marble tiles in the lobby were damaged........ so the floor covering contractor placed some men inside the lobby with chipping hammers to remove the cracked tiles in order to replace them.

Immediately adjacent to the hotel was a convention center (another piece of the project) and at the 3rd floor level there was an air lock entrance in the hotel where you could exit the building - cross an elevated promenade and gain access to the convention center (this is open air - not enclosed).

Understand that the structure of the 2 buildings are not physically connected in any manner except for one column in the hotel that rests on a pile cap that also supports a concrete wall that forms the end of the convention center structure. (A pile cap is a thick concrete "cap" that rests on (in this particular case) reinforced concrete piles driven deeply into the ground for support).

With the exception of that one common point of connection the structures are separated with a 5" air space (required because the structures sway in the wind - and if they ever touched each other under high wind conditions there would be a catastrophic collapse).

The concrete slabs of each building also have this one cap as a common point of bearing.

OK - the people working on the repairs were about 40 to 60 feet away from the cap in question - no damaged tile was closer to the cap than that - and I was speaking with someone outside of the building on the promenade - 3 stories up - with the doors into the hotel closed - when I realized that I could hear (very clearly) the chipping hammers as the workers used them in the hotel lobby.

It took me a few minutes to figure out what was going on - but I finally pin pointed the source of the sound. It was coming from a railing outside of the building.

Apparently the frequency of the chipping hammers striking the concrete was just right to send that transmission through the slab - into the concrete wall supporting the promenade - and was the perfect frequency to excite the aluminum rail assembly - which was vibrating like crazy and ringing.

In order for you to appreciate this fully you must understand that a small chipping hammer striking a concrete surface creates a high frequency sound - which does not have anywhere near the energy that low frequency sound has.

The path that sound takes (or can take in any case) is not as simple to analyze as it might seem at first glance. Stopping those transmissions is generally challenging even when the pockets of those willing to invest a lot of money are really deep.
Old 18th December 2010
  #12
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avare's Avatar
 

Thank you for a great example of a sound path Rod!

Andre
Old 18th December 2010
  #13
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Rod Gervais's Avatar
 

Quote:
Originally Posted by avare View Post
Thank you for a great example of a sound path Rod!

Andre
Andre,

my pleasure sir.....
Old 20th December 2010
  #14
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Thanks for all your replies--Rod, your anecdote clearly illustrates that my pockets would have to run pretty deep to make absolutely sure I'd be achieving the amount of isolation I set out to achieve, which is exactly the honest, informed opinion I wanted to hear. For me, this scenario reinforces a statement made on numerous acoustic threads here, that most aspects of acoustics are non-intuitive. It seemed reasonable to me that double drywall panels and plugs in the windows should at least reduce dB levels bleeding through the walls dramatically--I wasn't striving for perfect or even close to perfect isolation, but now it is apparent that even the goal of cutting 40 dB requires a very thorough approach specific to the structural details of the space including any unforeseen resonances and leakages, some of which I may not be able to locate and address without specific equipment, calculations and budget.

Basically, it makes a lot of sense that EVERYTHING must be considered and SIGNIFICANT masses are required in order to achieve full isolation. It is not as intuitive, however, to figure that similar measures must be applied when I'm OK with having as much as 60 dB still bleed through the walls. Acoustics is a very nuanced science indeed.

We may try the JamHub + headphones approach, but first we're just going to make a conscious effort to play quietly. The neighbors will still hear, but it won't be blaring, and like I said, they're OK with some noise. This approach will very likely give us much more control over our dynamic levels, which is a good thing all around. I never really wanted the rehearsals to get up to 100 dB (and maybe that's even a generous estimation), but we seem to be subject to gradual increases in volume as the rehearsal progresses--one person tries playing over the other, then the other person raises their volume, only for the initial person to raise their volume over that....you know the story. This is something we really do need to curb for the sake of controlling dynamic variation within our songs, so simply being vigilant about the level at which we play seems to be the best course of action.
Old 23rd December 2010
  #15
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Daveguy's Avatar
 

Move your rehearsal space to a diff location!

I would have to agree with some of the other posts, man. If you could move your rehearsal space to somewhere affordable and where you're least likely to disturb neighbors, then go for it.

However, if you need something temporary, some Audimute Sound Sheets can help reduce the levels of intensity in the space, decreasing the overall sound pressure you're experiencing. By no means will this block the transfer of sound from one room to the next, but it will reduce sound from going through to your neighbors space. Ideally, you would want to create a 'room in a room' type concept, where you build an enclosed room inside what you have with barrier products.

I still highly recommend moving your rehearsal space to somwehere affordable! I know many of people who have done so in NY!


Dave
Old 26th December 2010
  #16
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jhbrandt's Avatar
Daveguy,

You may have inadvertently given me another site to list on my VooDoo page. Be careful ascribing sound blocking abilities to a rubber sheet.

**the cheapest and most effective 'poor man's' sound proofing is another sheet of gypsum board.**

That company should have STL data for their 'sound blocking' products (from an independent laboratory).

I would never recommend a product without testing data.

Cheers,
John

Last edited by jhbrandt; 26th December 2010 at 04:22 AM.. Reason: forgot link
Old 26th December 2010
  #17
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Rod Gervais's Avatar
 

Quote:
Originally Posted by jhbrandt View Post
Daveguy,

You may have inadvertently given me another site to list on my VooDoo page. Be careful ascribing sound blocking abilities to a rubber sheet.

**the cheapest and most effective 'poor man's' sound proofing is another sheet of gypsum board.**

That company should have STL data for their 'sound blocking' products (from an independent laboratory).

I would never recommend a product without testing data.

Cheers,
John
I have to agree completely with John (not all that surprising), what this company advertises on their site is pretty much deliberately misleading. If their product makes any significant difference then there must be voodoo magic involved.

A little bit of the basics here - just so you understand why we are saying what we are saying (just saying so without explaining is akin to the claims they make (as to what their product does) without empirical data to back it up).

Let's suppose (for a moment) that the installation of their blanket made the room completely anechoic (we know it doesn't - we know it can't - especially at low frequencies - room modes will still dominate, and even high to mid frequencies will still build up because the materials can't absorb 100% of the energy) - but (for the purpose of this analysis) lets just make believe it does.

In a completely anechoic room what are you left with when all is said and done?

You are left with the original signal - the direct signal - this is not (and could never be) changed (reduced) in any manner by the installation of ANY room treatments.

Ok - so now we have the original 100 - 110dB sound level making it to the face of the blankets Dave provided the link to........

Basically mass law states that for every doubling of mass you acheive a 6dB reduction in transmitted sound - now - a sealed air space adds some to this - as does the installation (within the wall cavity) of fluffy insulation (slightly better bang with this then the more dense insulations at lower frequencies).

However - once the wall itself is constructed - the addition of mass comes very close to the predictions based on mass law. SO (for the purpose of this exercise we will just look at what you would have to do to obtain another 6dB reduction in isolation.

5/8" gypsum drywall weighs about 2.5 pounds per square foot - and this is the most typical material used for the fire separation walls between tenant spaces.

If we assume only one sheet of drywall on each surface - that would mean a total of roughly 5lbs of mass per square foot of wall surface.

So to achieve an additional 6dB of isolation we would have to add 2 layers of drywall to the inside face of the wall between the units.

Let's look at the products this company provides in that regard.

The Audimute Sound Sheets add .2916 psf to the existing wall.

Looking at the products they really recommend for increasing sound isolation (Their Peacemaker Series of Recycled Rubber Sheets)

The PM 2mm adds .32psf of mass.
The PM 3.2mm adds .7psf of mass
The PM 6.4mm adds 1.06psf of mass.

Now - I will grant you that there is some small added benefit to the fact that these are not rigid panels - however placed inside of a wall assembly (rather than within it) this is not a significant enough addition to make up for the loss of mass.

So in the best case scenario (PM 6.4mm) - you can increase the mass by (roughly) 21% - a far cry from doubling.

However - to really make this meaningful - lets finish the analysis by looking at the cost of each application on a per square foot basis.

5/8 inch drywall can be purchased for roughly $12 for a 4x8 sheet - so about
37.5 cents per square foot - thus 3/4 of a (US) dollar per square foot to double the mass.

Let's look at what it costs for the PM 3.2mm (they do not recommend the 6.4mm product for walls - this is intended primarily as a floor product to reduce impact transmissions)

You can purchase a 2 x 25 foot roll (50sf) for $60.00 - so around $1.20 per sf of wall coverage.

Now (and you need to think about this for a minute - just to get it clear in your head) they were willing to pay a certified lab to test their product - In this case they used Riverbank Acoustical Laboratories - a respected and certified testing lab - so there is no question in my mind that the reported results are accurate - and I am pleased to see that they post the actual report on their site - in it's entirety.

However - the test they performed is a test that reflects nothing that would exist in reality - instead of constructing a wall that would be similar to their recommended use of the product - they tested the bare product itself.

The test opening in question at RAL is 8' wide by 8' high - so around 50 dollars worth of drywall and perhaps 20 dollars in wood framing - maybe an extra hour of labor to construct.

Let's call it 150 additional dollars on top of the monies they spent for testing (certainly not a significant addition to the overall cost of testing).

One has to wonder why they would not spend the pennies involved to be able to present real data to the people they are marketing this product to.

The only answer I can come up with (in my imaginative mind - for I certainly was not a part of the decision making panel in this endeavor) is that the product does not add what they want the public to THINK it adds to the equation.

They present the RAL numbers as if these are the additional results you can achieve with their product - BUT - reality (and this is reality - this is not a supposition on my part) is that the individual isolating values of materials involved are not cumulative when you take those same materials and utilize them in an assembly.

This is proven fact - there is no argument (data based) that anyone could offer to indicate otherwise.

These products are not worth anywhere near the values that could be realized by simply installing even a single sheet of additional drywall to the wall in question.

If a company is not willing to provide real life test data to allow the purchaser the make an informed decision as to the value of the product in their particular situation - then all we are looking at is snake oil sales in action.

Sincerely,
Old 27th December 2010
  #18
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jhbrandt's Avatar
Quote:
Originally Posted by Rod Gervais View Post
They present the RAL numbers as if these are the additional results you can achieve with their product - BUT - reality (and this is reality - this is not a supposition on my part) is that the individual isolating values of materials involved are not cumulative when you take those same materials and utilize them in an assembly.

This is proven fact - there is no argument (data based) that anyone could offer to indicate otherwise.

These products are not worth anywhere near the values that could be realized by simply installing even a single sheet of additional drywall to the wall in question.
Emphasis added.

Acoustics is non-intuitive. Many sellers prey on that fact and the assumptions of many unsuspecting... That is why Rod and many other professionals, including myself, are here.

Rod, may I quote you on my VooDoo page? I do think that I shall add them to my list.
Cheers,
John
Old 27th December 2010
  #19
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Rod Gervais's Avatar
 

John,

You can quote me anywhere, any time of your choosing (always).

Rod
Old 5th January 2011
  #20
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Mitch Z's Avatar
 

Response to John Brandt and Rod Gervais

Audimute is a family owned business in Beachwood, Ohio. We actively seek feedback and ways to improve our service, products, and ability to interact with others interested in solving acoustics problems. We are open and honest about what you can expect (and shouldn’t expect) from the products we make and sell. We have thousands of happy customers, and we follow up after every purchase to make sure anyone who purchases a product from us gets what they wanted and what they were promised. If there is a problem, we fix it. Our only concern is the value of the solution to the customer.

We also produce videos and create informational resources and make them freely available on our website to anyone who wants to educate themselves about topics related to acoustics and solving acoustical problems. To experts in the field, some of these materials may seem over simplified. But to make an informed decision, the average person needs the bird’s eye view of the terrain.

I respect your knowledge and experience, and I would imagine that your methods are effective. But to a hammer, every problem looks like a nail.

JPickles said, specifically, he’d like to spend under $1000 to solve this specific problem. I’m on the phone every day with people, probably people like JPickles, who can’t afford thousands of dollars for the “perfect” acoustical solution you would recommend.

There are legitimate options for making affordable, incremental steps to improve acoustical performance using sound absorption and/or sound barrier products. To say that someone suggesting otherwise is a liar or deceptive is inappropriate and false. Often, simply the introduction of sound treatments in a space where they have not been before is enough to meet the needs and expectations of people trying to improve their acoustics.

The essential points DaveGuy made were:

1) Best solution is to move to another rehearsal space
2) As a temporary solution, Sound (Absorption) Sheets -- he could have recommended sound absorption material -- will help to reduce the intensity of the sound in the space…but will not block the transfer of sound from one to the next.
3) If you can’t move spaces, the best solution is a Room-in-a-Room concept using sound barrier products.

Which of these 3 points do you find so misleading?

I take the feedback about the Peacemaker tests seriously. We could improve on our presentation of test results and design. Unfortunately, we have not found a better testing solution because, as you know, every space, every construction material, every application is different. No test, no demonstration can accurately reproduce or measure the effect of any sound treatment generically. We only control the quality of our product, and so that is what we measure.

We want to be of value in this forum and others. If you can help us provide better service and more value, we want to listen and adapt. If you just want to try to attack and discredit us, you’re doing no one a service.

Sincerely,

Mitch, Musician and President of Audimute

Last edited by Mitch Z; 5th January 2011 at 07:40 PM.. Reason: Added credentials
Old 5th January 2011
  #21
SAC
Registered User
 

Your product may have infinitely large STL/NRC and any other sound transmission abatement values you might desire attributed to it (despite the limitations with regard to the transmission of full range music that they all share!).
In fact, it may be the densest most inert material in existence. (And for what it is worth, there are standard tests for the evaluation of the sound transmission through wall surfaces that are useful at least for the purposes of comparative purposes.**)

And all is for naught, as Both John and Rod have pointed out, if the flanking vectors are not addressed. So it is NOT as simple as installing a surface treatment.

It seems that everyday folks show up having read some brochure thinking that if they only buy lots of that one product - be it some wallboard, or glue or caulk or whatever, that it will miraculously solve complex problems. And seldom do those brochures accurately represent the total context and importance of addressing ALL of the various additional factors necessary to be addressed in order to achieve the desired response, of which their product may only address one.

And simply applying an isolated treatment without respect to the remaining variables is a waste of money and effort if those other variables are not effectively addressed.

Without the complete system of energy transmission paths being addressed, simply treating one makes little difference in the total reduction in sound transmission. No more than one's simply acquiring a Stradivarius violin would make them an exemplary violin player. Or it is common to read threads where someone is under the impression that buying some exorbitantly priced mic pre-amp, improving the existing noise component from .000x to .00000x, will make a significant difference while their room featuring a 70 dB noise floor! ...There is just a bit more involved in the process.

And if one is not prepared nor qualified to assess and address all of these variable, selling them only one component and leading them to expect a significant improvement is not only an expensive disservice, it borders on misrepresentation, as the product, in itself, is not a complete solution.


And this, as stated, not only reflects this isolated product as a solution view,:
Quote:
Originally Posted by Daveguy View Post
However, if you need something temporary, some Audimute Sound Sheets can help reduce the levels of intensity in the space, decreasing the overall sound pressure you're experiencing. By no means will this block the transfer of sound from one room to the next, but it will reduce sound from going through to your neighbors space.
but it is simply incorrect (and the last sentence self-contradictory!). Unfortunately, this is exactly the impression many have from ready brochures and product descriptions that focus on the material itself, and not the total scope of what is necessary to address the issue of sound transmission.

No one should walk away after reading promotional literature with such an incomplete understanding of the function of a product.

**And as far as not having a means to evaluate the performance of such a product, you might find this and other publications useful. It also specifies the testing methodology. The forum editing tool says it is already attached - maybe you can find it! - in any event, here is the link to the PDF:

www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/ir/ir761/ir761.pdf
Old 6th January 2011
  #22
Gear Addict
 

Not surprisingly, we have found that most of these barriers are simply standard 1# or 2# MLV. (I realize the aforementioned products are simply common recycled car tires dispatched into crumb rubber). Many companies add a brand name, and that's fine, however there are only a handful of actual manufacturers of MLV, though many re-sellers unfortunately claim to have some proprietary "visco-elastic" formulation that they alone control. That's the downside of marketing.

There's not a lot that can be brought to the table in terms of MLV performance beyond what is attributable to mass.

I've personally been involved with the measurement and testing of several brands of MLV (even brands that fight tooth and nail to distance themselves from a perceived MLV stigma by strongly claiming not to be MLV) over the years and have found that all perform about the same, essentially. Test results are as expected given the mass. Could be installed constrained between drywall, could be limp on the studs before drywall. All with similar results. That’s not a bad thing, nor does this mean MLV is a bad thing.

MLV certainly has its place, such as when a super thin layer is all that can be accommodated.

MLV is heavy, but drywall is also.

MLV doesn't effectively damp what it is contact with (drywall), although it is often purported to do so.

MLV is sometimes paired with a thin layer of fiberglass for a small amount of surface absorption. This is helpful with construction site sound barriers, but not for soundproofing efforts.

MLV is essentially starts as a Poly Vinyl Chloride (PVC) semi-liquid. This lighter weight plastic is then “loaded” with a heavy powder to give the MLV its characteristic mass. The heavy powder used to be Barium Sulfate, but today most manufacturers have gone to Calcium Silicate for the source of mass.

It’s important to use a vinyl that uses polymeric placticisers rather than the cheaper monomeric. Also look for extruded rather than cast, as cast MLV is quite weak.
Old 6th January 2011
  #23
Gear Guru
Claro

Wow, thanks Ted.

DD
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