NY Times article on home recording and soundproofing

AlChuck

Well-known member
For Musicians, Solid Walls Make Good Neighbors

February 21, 2004
By SABRINA TAVERNISE

Jay Braun, a guitarist for a New York City rock band called the Negatones, is well versed in the science of soundproofing.

"Sheetrock, sound board and plywood, over and over," said Mr. Braun, a fast-talking 32-year-old who has put up soundproofing in two New York City living spaces. "We really did want to be good neighbors."

Although musicians began recording in their homes as early as the 1970's, the migration away from professional studios to homes expanded in the 1980's, as drum machines and multitrack tape recorders came into widespread use. Now that computers and recording software are household items - new Apple computers come with a program called GarageBand - recording at home, for musicians, has become routine.

"It's becoming harder and harder to find people who do not have their own home studio," said Alan Fierstein, a SoHo-based acoustic consultant, whose own professional studio, Sorcerer Sound, recently closed.

"Twenty years ago, a studio was the only place you could make music," said Russell Simins, drummer for the Jon Spencer Blues Explosion, a New York City band.

"Ten years ago that was less true," he said. "Now studios are being avoided. People have computers. They sit at home."

But with home studios came the noise. And the efforts to contain it.

"It's the neighbors that create the soundproofing equation," said Gary Silver, a sound designer who has been soundproofing homes and professional studios since 1984. "New York being what it is, that really makes it a problem."

For Michael Mehler, who lives directly below a home studio in a building on the Lower East Side, the most frustrating thing about the musician upstairs is his choice of instrument. "Jumping up and down with the electric guitar is different than playing Bach," Mr. Mehler said on a recent Saturday. "It's not like he's a violinist."

Mr. Mehler added that the musician "could do it with headphones."

That is precisely the advice offered by Richard Murdock, a property manager in Manhattan, who has had to handle complaints about a tenant with a studio in a Lower East Side building.

"That boom boom boom, and the rattling of the dishes," he said. "Most of these old tenement buildings are not steel and concrete. Playing live music in an apartment, it's impossible not to encroach upon your neighbors."

Muffling music is often harder than it seems. The first mistake, Mr. Silver said, is the assumption that sound can be trapped in a room by putting up some carpets. "I constantly have people talking about foam, fabric and
egg cartons," he said. "You need mass. Sheetrock, concrete, wood. Expensive, heavy things have to be built."

Mr. Braun, like most people, began on the low end of the learning curve.

His first attempt at soundproofing came in 1996, when the band rented part of an artist's loft in Williamsburg. The band members marched to a Home Depot and bought plywood, and slabs of Sheetrock and layers of soundboard.

"We thought we were so sophisticated," recalled Mr. Braun, dressed in a rumpled suit jacket and sneakers on a recent Thursday afternoon. "We were all high-fiving each other up to the time we brought in the bass and the drum set."

But the new walls had a puzzling effect. Instead of sounding softer, Mr. Braun said, the music "seemed to have gotten louder."

It was a defining moment. Mr. Braun realized that "there is, in fact, a reason for science."

The band left the building. For a while, they rented part of a woodworking studio, where they played among table saws. Meanwhile his peers were playing in rented Manhattan Mini Storage spaces.

Mr. Braun began wrestling with physics in a basement space on Stanton Street. He hired a carpenter to design an elaborate semi-suspended ceiling in the space, which was not supposed to be lived in, but often was - several of the band members called it home from time to time. The ceiling was made of five layers of material: particleboard; two
layers of sound board, which functions as a thick cushion; plywood; and Sheetrock.

"Sound is like water," said Mr. Braun, flanked by a laptop computer and a console in the band's newly rented recording space in Williamsburg, Brooklyn. "If you drill one hole in the wall, the sound will leak right through."

Month after month the band added new layers. They removed a water pipe that carried sound into a neighbor's apartment. They spent $20,000, by Mr. Braun's calculation. "We became handymen," he said.

They recorded albums in the space in the meantime, not bothering to wait for perfection. But the noise and activity was eventually noticed by city inspectors, and they were given two months to leave.

Mr. Fierstein said that many penny-pinching musicians skipped soundproofing altogether. Instead, bathrooms and closets become recording spaces.

"People can't afford soundproofing, but they have to have the ability to record a singer," Mr. Fierstein said. "The bathroom is the closest thing to a concert hall."

As more musicians stay at home to make music, professional recording studios have suffered. Bill Tesar, the owner of the Toy Specialists, a large sound equipment rental company, said improved technology for home recording and reduced budgets from record companies have caused business with studios to decline over the past three years. His
company, in business since 1983, closed last week. "I'd say more than 60 percent of the midsize recording studios that were in business five years ago are now out of business," Mr. Tesar said. "That's not an inflated guess. There were literally hundreds of them in the New York metro area. Now, if there are 40 or 50, that's a lot."

Even freelancers are worried. Adam Kendall, who plays in an electronic music group and also records bands out of his apartment in Park Slope, Brooklyn, says he is concerned that the amount of work he's had the past several years will decline.

"I'm the person big studios hate," he said. But he added that Apple's release of GarageBand "is my karmic return."

He added, "I gave up hope for making money recording music."

Some musicians said home studios and computer equipment were making recording quieter. Richard Bernstein, lead guitarist for Rammstein, a German heavy metal group, said the recording process was less collaborative now, more a solitary plinking on a computer keyboard than a group playing effort.

"You don't have to listen loud anymore," said Mr. Bernstein, whose concerts feature feats of pyrotechnics.

Music today is "everyone is cooking in his own kitchen by himself," he said, in his home studio on the first floor of a former firehouse on Lafayette Street in Manhattan. "It used to be five guys playing together, but that doesn't happen as much anymore."

"You can do everything without other people's presence," Mr. Bernstein said.

Besides, says Mr. Kendall, "am I really making more noise than a guy on Sunday who is watching an Arnold Schwarzenegger movie in surround-sound?"

There are those musicians for whom such questions are not rhetorical. Howie Statland, the musician who lives upstairs from Mr. Mehler, said he could not afford soundproofing and, even if he could, his neighbors' blaring music and yelling children would give him the right to make noise
freely. He has a guitar amplifier in his bedroom and plays often. Drums were his one concession.

"The guy downstairs gets upset when I put the guitar too loud," Mr. Statland said.

A basic philosophy, however, prevails. "I've had people yell, `Shut up,' but they're out there, and I'm in here. What are they going to do?"

Not everyone records at home all the time. Many musicians still use large studios for much of their final products.

"People who are making big money music are still going to the two or three big studios in Manhattan," said Mr. Simins, whose own small recording studio is not in his home. "Britney Spears doesn't sit at home in front of her computer."

As for Mr. Braun, he sums up his hard-earned wisdom in soundproofing succinctly. "You can follow the rules note for note, but if you have an old lady sleeping downstairs, that's it," he said.

Recognizing that there are advantages to a separate studio, his band rented one in Williamsburg last year. The main criteria: no soundproofing required. The studio is in an industrial zone on a corner, just beneath the Williamsburg Bridge.

http://www.nytimes.com/2004/02/21/nyregion/21NOIS.html?ex=1078388012&ei=1&en=7f9ca1022384eccc
 
Negatones in the TIMES !! Hell Ya

Hey I saw this article, and way to go Jay !!!!! It's Dano, I was assisting on your sessions over in Hoboken. Luv the Rosk Star pic of you guys in the Times !!

By the way, if you guys want to catch a truly entertaining, and talented band, check out the Negatones,,,,,,at negatones.com Jay and the crew are seriously out of thier minds,,,,,,in a good way of course.

Cheers to Jay, Justin, Jun, and Jesse, you guys f**kin rock!

-Dano

PS- I want some hot for teacher next time I come to catch the show!
 
Theres one thing they forgot to leave out of the article.

INSULATION.

and another thing:

DOUBLE FRAMED WALLS (preferably metal studding)

Plenty of talk about Sheetrock/drywall... and soundboard (which I assume they mean Homasote... )... but to forget to tell people about insulation is a deadly mistake.

I fancy myself as a newfound laymen/expert in soundproofing as I now have severak small soundproofing jobs under my belt... and I've pretty much went through what this guy went through with the experimenting and looking up all the latest designs on the internet.

Theres all kinds of fancy schmancy types of insulation you can buy... some of which have phenomenal low frequency specifications.... however... after having "real world" experience and busting through some old myths..... and marketing hype.... I actually learned that good ol' fashioned "pink" (Corning) or "yellow" (CertainTeed) insulation works absolute miracles.

I reccommend two 3 inch layers.... as opposed to 1 6 inch layer... because for whatever stupid reason 3 inch insulation really aint 3 inches, and 6 inch insulation definately is not 6 inches think but less.... so go with the double 3 inch.

The more insulation layers the better [see next paragraph].... because if you buy enough of the stuff you should have stuff left over to put an extra layer in the more critical walls... anything thats against a cement wall only needs one or two layers... but for adjoining rooms you need to make the mass thicker and add more insul....

Also,... just as with adding mass.... as well as increasing the wall thickness.... adding insulation follows the laws of diminishing returns.... Its exponential. 2 layers of insulation makes a BIG, BIG difference in comparison to one layer.... but if you add a 3rd layer, the difference is alot less.... Don't ever go passed 3 layers or your just wasting money... The 4th layer of insulation will make virtually no audible difference unless your doing a lab test and measuring it exactly in a controlled enviroment.

Walls should be steel studs (actually cheaper than wood) [subject to some opinion there].... and should always be double walls when your dealing with 2 adjoining rooms... Walls should be double framed and 6 inches thick MINIMUM and if you really need to sound-proof something (i.e. a control room, or an isolation singing booth if you have a really noisy noise like I do...) you want the walls to be double framed and 8 - 12 inches thick... no more or your just wasting space...

Space the studs 24 inch on-center, preferably.... but I know this pisses many carpenters off.... but tough... their locked in their ways for no good reason since 16 inch o.c. is also arbitary. 2 double layers of 5/8th produces a wall that is more than thick enough to handle the 24 inc o.c. spacing.

We could get into resilient channels and such. I went down that road and did some experimentation. You can achieve excellent results without it. Its kind of a hassle... but not that big of deal if you really want it. The stuff is just kind of hard to get hold of though if your in a pinch to get the project done.... which is the same issue you get if you want to order exotic insulations.... with high TL's at low frequencies..... forget it... stick with regular insulation.

You don't need special "acoustic" insulation either from Home Depot... Your just foolishly paying more money for the same exact crap. Acoustic or "unfaced" insulation has no vapor barrier or facing (no Kraft paper)... you actually pay more for no paper... waste o' money.. Just buy the true 24 inch (not 23 inch) Kraft paper insul and rip the paper off it.

There is actually some theory about whether you should leave the paper on or off, and theres also theory about whether the Kraft paper should face it into or out of your studio. It DOES makes a difference... I've test this for a fact... but I'm not going to elaborate in this brief message.

Sheetrock should always be 5/8th inch thick... although 5/8th sheetrock is a real bitch and a half to lug.... that stuff is heavy!
The sheetrock should be double 5/8th on each side making a total of 4 layers.... You could go thicker than 4 layers by adding a layer in the middle between the two framed walls.... but if you double insulate the walls.... its not necessary... you'd just be wasting time and energy by adding a 5th layer of sheetrock..

If you intend to build a "room within a room"... you need to have alot of carpentry experience needless to say to build this... but you need to make damned sure that your "room within a room" is actually not touching the preexisting frame except on the floor.. This sounds easier said than done... trust me... build a few soundproof rooms and see.... metal studs can be hard to work with... don't permanently affix the inner wall to the outer wall to hold it up... If you put braces in temporarily.... take them out when the frame is all locked into place.... otherwise the braces will transfer vibrations from the outer wall and house.... right into your studio.

ALL spaces (sheetrock and floor tracking) should be THOROUGHLY, THOROUGHLY, THOROUGHLY sealed with glue.... forget about that BS* "acoustic glue"... stuff.... just use "Liquid Nails for sealing cracks... (available at Home Depot)... I also suggest you use PL-400 adhesive for framing where you can... don't use the PL-400 for filling cracks because its too thick and goopy and doesnt apply easy... The Liquic Nails is very thin mixtured and you can easily apply a bead quickly to fill gaps in sheetrock and make sure you fully glue the metal or wood stud tracking to your floor so that sound cannot leak under the wall...
 
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Industrial said:
Theres one thing they forgot to leave out of the article.

INSULATION.

and another thing:

DOUBLE FRAMED WALLS (preferably metal studding)


Agreed on both counts with one comment - the metal stud framing is only preferable if it can be light guage. Light guage metal framing creates a better STC rating than just wood or heavy guage metal - actually the equivilent of wood framing with RC on one side - HOWEVER - if the wall needs to be bearing (i.e.: carrying an innner ceiling on the walls of a true "room within a room") then the wood framing is less expensive than heavy guage steel studs.

Plenty of talk about Sheetrock/drywall... and soundboard (which I assume they mean Homasote... )... but to forget to tell people about insulation is a deadly mistake.

Agreed on the insulation issue - however homasote is a waste of money (not suggesting that you said it was any good - just a note).

I fancy myself as a newfound layman/expert in soundproofing as I now have several small soundproofing jobs under my belt...

You do have more knowledge than most newbies - but are not quite a layman/expert yet - you have a few mistakes in your comments here - read on to come closer to Acoustic Nirvana:


Theres all kinds of fancy schmancy types of insulation you can buy... some of which have phenomenal low frequency specifications.... however... after having "real world" experience and busting through some old myths..... and marketing hype.... I actually learned that good ol' fashioned "pink" (Corning) or "yellow" (CertainTeed) insulation works absolute miracles.

I reccommend two 3 inch layers.... as opposed to 1 6 inch layer... because for whatever stupid reason 3 inch insulation really aint 3 inches, and 6 inch insulation definately is not 6 inches think but less.... so go with the double 3 inch.

The more insulation layers the better [see next paragraph].... because if you buy enough of the stuff you should have stuff left over to put an extra layer in the more critical walls... anything thats against a cement wall only needs one or two layers... but for adjoining rooms you need to make the mass thicker and add more insul....

Also,... just as with adding mass.... as well as increasing the wall thickness.... adding insulation follows the laws of diminishing returns.... Its exponential. 2 layers of insulation makes a BIG, BIG difference in comparison to one layer.... but if you add a 3rd layer, the difference is alot less.... Don't ever go passed 3 layers or your just wasting money... The 4th layer of insulation will make virtually no audible difference unless your doing a lab test and measuring it exactly in a controlled enviroment.


All of that having been said - rockwool (Thermafiber) insulation (also known as fire safing) gives a better rating at lower frequencies due to it's increased mass. 2 layers of 3" (one within each frame of a 2 frame wall assembly) is about the premier insulation for this purpose.

He is right that you can reach a point where incerased insulation does not give enough return on the investment to make it worth while.

Walls should be steel studs (actually cheaper than wood) [subject to some opinion there].... and should always be double walls when your dealing with 2 adjoining rooms... Walls should be double framed and 6 inches thick MINIMUM and if you really need to sound-proof something (i.e. a control room, or an isolation singing booth if you have a really noisy noise like I do...) you want the walls to be double framed and 8 - 12 inches thick... no more or your just wasting space...

On this I don't really agree - the main advantage to thicker walls at the control room would be ability to create a greater seperation of glass at the window - a decided advantage. But the gain in seperation for the wall itself is not as great as the addition of one layer of drywall - and one layer on each wall is ever more benefit.

For the comment on steel vrs wood - see my observation above.

Space the studs 24 inch on-center, preferably.... but I know this pisses many carpenters off.... but tough... they're locked in their ways for no good reason since 16 inch o.c. is also arbitary. 2 double layers of 5/8th produces a wall that is more than thick enough to handle the 24 inc o.c. spacing.

I have no idea why this (24" o.c.) would piss off any good carpenter - it's a standard framing dimension - 16" o.c. is not arbitrary - both are designed to work with standard material dimensions - i.e., 8' lengths of plywood or drywall - 12' lengths of drywall - etc. 16", 32", 48", 64", 80", 96" vrs - 24", 48", 72", 96".

HOWEVER - there is no STC advantage of 24" over 16".

We could get into resilient channels and such. I went down that road and did some experimentation. You can achieve excellent results without it. Its kind of a hassle... but not that big of deal if you really want it. The stuff is just kind of hard to get hold of though if your in a pinch to get the project done.... which is the same issue you get if you want to order exotic insulations.... with high TL's at low frequencies..... forget it... stick with regular insulation.

I agree that it isn't worth the investment to deal with "specialty items" that have no test data behind them........ stick with standard items that have lab tests backing them up.

BUT - RC adds an addition 3db in reduction when applied to one face of a wall assembly (or one face of a double wall assembly) - no gain for the second face.

HOWEVER - as i noted above - if using lightweight metal framing - there is no gain - only with wood walls of heavy guage metal framing.


You don't need special "acoustic" insulation either from Home Depot... Your just foolishly paying more money for the same exact crap. Acoustic or "unfaced" insulation has no vapor barrier or facing (no Kraft paper)... you actually pay more for no paper... waste o' money.. Just buy the true 24 inch (not 23 inch) Kraft paper insul and rip the paper off it.

There is actually some theory about whether you should leave the paper on or off, and theres also theory about whether the Kraft paper should face it into or out of your studio. It DOES makes a difference... I've test this for a fact... but I'm not going to elaborate in this brief message.


What you refer to as "acoustic insulation" (actually known in the industry as "sound batts" - is just a less dense fiberglass insulation.

It actually does help with standard STC walls due to the fact that STC ratings are really geared towards frequencies primarily in the range of the human voice - and not the lower frequencies which we are concerned with in studio construction. For regular fiberglass insulation you should not pay one penny more for faced or unfaced........ if you do someone is ripping you off - so just shop around.


Sheetrock should always be 5/8th inch thick... although 5/8th sheetrock is a real bitch and a half to lug.... that stuff is heavy!
The sheetrock should be double 5/8th on each side making a total of 4 layers.... You could go thicker than 4 layers by adding a layer in the middle between the two framed walls.... but if you double insulate the walls.... its not necessary... you'd just be wasting time and energy by adding a 5th layer of sheetrock..

1st off - never EVER put a sheet of drywall on any of the inner faces of a wall assembly - it will not raise the wall isolation value - it will actually lower it. Never mind - "not necessary" - try - "REAL BAD CONSTRUCTION"

This has been proved in labratory tests.

BUT - there is also some data that indicates that you can gain by mixing sheets of 1/2 inch with 5/8" in a wall assembly - due to the differing TL values of the materials.

Personally I take the "more mass is better" approach in my designs - and thus just use the 5/8" - however I would be remiss if i did not point out the other school of thought on this.

If you intend to build a "room within a room"... you need to have alot of carpentry experience needless to say to build this... but you need to make damned sure that your "room within a room" is actually not touching the preexisting frame except on the floor.. This sounds easier said than done... trust me... build a few soundproof rooms and see.... metal studs can be hard to work with... don't permanently affix the inner wall to the outer wall to hold it up... If you put braces in temporarily.... take them out when the frame is all locked into place.... otherwise the braces will transfer vibrations from the outer wall and house.... right into your studio.

I agree with this in it's entirety.

ALL spaces (sheetrock and floor tracking) should be THOROUGHLY, THOROUGHLY, THOROUGHLY sealed with glue.... forget about that BS* "acoustic glue"... stuff.... just use "Liquid Nails for sealing cracks... (available at Home Depot)... I also suggest you use PL-400 adhesive for framing where you can... don't use the PL-400 for filling cracks because its too thick and goopy and doesnt apply easy... The Liquic Nails is very thin mixtured and you can easily apply a bead quickly to fill gaps in sheetrock and make sure you fully glue the metal or wood stud tracking to your floor so that sound cannot leak under the wall...

Nope - sorry - liquid nails do not take the place of caulk - are not manufactured for that purpose and will not work - however you do not need to use acoustic caulk to get the job done either. Sika-Flex (for one example) is a good caulk for this purpose.

Liquid nails will harden over time - and the critical condition for any caulk to work acopustically is for it to stay pliable......... acoustic caulk is often refered to as "floppy caulk" due to the fact that it never hardens.

Liquid nails is not made for sealing cracks - it is a construction adhesive.

The proper installation is as follows:

Do not bother caulking the sill to the floor - that is not going to be the sound path - the sound will then travel below the sheetrock and up the back face of the drywall (over the bottom plate) and the same on the other side - thus through the wall - This is actually detailed in the USG manual.

Rather - install the wall - then the 1st layer of drywall - and caulk all 4 edges - hold the drywall 1/4 to 3/8" away from all edges to do this properly. Then caulk the joints in the field.

Do this all the way around the room for all 1st layer wall and ceiling edges and joints.

On the 2nd layer - follow the original installation path and do the same thing - except for the joints in the "field". Make certain to hold the caulk at the edges in slightly from the drywall face to allow for proper taping of the product.

Now tape as usual.

Be sure to overlap your joints on the drywall so you have no direct passage ways for sound to travel in the event of a failure of the caulk or tape.


Industrial,

Out of a possible score of 1 to 10 - I would give you an 8.5 - which is pretty good for a newbie - but not quite a layman/expert.

By the way - I do this for a living - day in and day out......... I am what some consider an expert in the field. Of course there are others who just consider me a pain in the arse.

Sincerely,

Rod
 
ROD REPLIES> HOWEVER - there is no STC advantage of 24" over 16".

--------------------------------


Before you read the following... I'd like to know what you
think of a product known as "Quiet Rock" ever use it?

Just wondering if this is BS* hype...

Here is a web link to the company:

http://quietsolution.com/construction___building.html

Supposedly, the installation of their sheetrock can
take the place of the resilient channel (which has its own
associated problems as you know with shorting out)...I'm
just wondering if you yourself or anyone you know has used
this product.

Here is just one of their white papers.

http://quietsolution.com/Cost_Benefit_of_RC_vs_QR_scn.pdf
----------------------------

Also, what do you think of the practice of gluing the second layer of sheetrock onto the first? You think it has any measurable benefit? Think its a waste of glue?

Whats your usual method, do you just screw the second drywall layer into the first (without screwing into the studs)?... or do you think its acceptable to just screw the second layer into the studs?

Personally, I think its bad practice to screw the second drywall layer into the studs... so I usually don't do that.

The one nice thing about gluing the second layer is that you have no exposed screws... so that lessens your spackling job.

-----------------------------
There are two issues here:

(1) Free Space Loss, and
(2) Transferance of mechanical vibrations.

HOMASOTE is reccommended by manufacturer "White Papers" primarily for the latter reason, not the former.

Much like you, I cam to the conclusion that Homasote is kind of a waste of money.... money that at the very least could be better spent buying more 5/8th inch rock.... Being an electrical engineeri, I did some fairly sopisticated tests and collected data in a controlled enviroment.

I tested different thickness sheetrocks as well as Homasote, as well as many of the top end types of insulation and compared it to regular insul batting... and I did this at all different frequencies... One day I'll collect and post my data... although I doubt my results are any better than the specs which are already out there in the manufacturer white papers.

My conclusions from several months of testing is that:

(a) Homasote is a waste o' money, although I did measure a small difference between 1/2 rock and 1/2 homasote... but waste o' money nonetheless.

(b) I also concluded that a regular home studio should likely not spend the extra money on better types of insulation unless the owner really wants to and is willing to take the time to special order stuff unless they really are determined to abate low frequency sounds (i.e. if their going to be playing drums, or if low frequency mechanical noises and foosteps from above are a persistant problem. I believe the regular insul if you go with two 3 inch layers will abate much of the mid to high frequencies such that you can achieve 58 - 63 dB loss fairly easily at the mids to highs).


Its not all about STC/TL..... It is also about mechanical vibrations...
This is VERY important in some enviroments; especially home studios where the predominant factor may be family members pounding on the walls, and floors, and ceilings. This is aparticular problem is the studio is built in a basement, like mine is.

While I question the beneficiality of 24 o.c. spacing for
free space losses... I would not be as quick as you to
dismiss it. Changing the spacing does have a very real
physical affect on the structure.... in fact the effect
can be likened to the physics involved in a resilient channel....
its about modulus of elasticity... and it also involves
a change in the volume of air space behind the drywall
and between the studs.

Regardless of how the stud spacing actually affects the free space propagation loss.... I'm still conviced that it does play a very strong role in mechanical vibrations since the distance between the studs plays a role in the flexibility and absorption characteristics of the sheetrock... or whatever the deeper physics is behind the wider stud spacing.

I have yet to see a White Paper, and I've read literally hundreds
of them on resilient channels and wall design from the different manufacturers of gpsum board and university studies which specifically state in numerical tests, that 24o.c. makes a difference. I don't know if anyones ever determined the physic behind it all.... but thats what the white papers say... and so thats what I stuck with in my design.

---------------------

Also, while acoustic caulk is supposed to be "non-hardening"
(or "non drying")... and thats doing it by he book... I still
see little problem with using structural adhesive, whether
it dries or not.

Sound takes the path of least resistance and it will travel
within reason through any open channel be it anopen door, or an open window.. or a gap between sheetrock. You close that gap via any means whether it be with taping and spackle or with structural adhesive)... and the pressure wave finds someplace else to go.
 
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One question -- I thought it was advantageous to mix the thicknesses of the wallboard so that they would resonate at different frequencies? (as opposed to always using 5/8)

-lee-
 
One question -- I thought it was advantageous to mix the thicknesses of the wallboard so that they would resonate at different frequencies? (as opposed to always using 5/8)
--------------------------

Ahhh, yes.... you've observed some of the literature correctly. I've never seen any good data from the manufactureres on how much this actually makes a difference.... but that is the prevailing theory.

However, this is where you run into "real world" paracticalities which clashes with theory.

You could install one layer of 5/8 and one layer of 1/2 inch.... but according to all the specs from manufactureres out there... this just isn't going to give you the TL that a double 5/8th will...

(5/th and 1/2 inch still isnt that bad and provides very good results for home studios if you dont want to go overboard...)

So then your left with the only other option... 3 layers of sheetrock ....[ 5/8th and 1/2 and 58th]... you do this on one side... and then maybe only a double layer (5/8th and a 1/2 layer on the other side)... so then your installing 5 layers instead of 4... plus your alternating the thickness, which is good theoretically.... but 5 layers of sheetrock is a hell of alot of work (4 layers is already enough work as it is).
 
Industrial said:
Before you read the following... I'd like to know what you
think of a product known as "Quiet Rock" ever use it?

Just wondering if this is BS* hype...

Here is a web link to the company:

http://quietsolution.com/construction___building.html

Supposedly, the installation of their sheetrock can
take the place of the resilient channel (which has its own
associated problems as you know with shorting out)...I'm
just wondering if you yourself or anyone you know has used
this product.

Here is just one of their white papers.

http://quietsolution.com/Cost_Benefit_of_RC_vs_QR_scn.pdf


I've studied the product in the past........ however - have never used it.

Standard construction practices do produce good results as long as careful planing takes place.

One of the products that our company produces is hotels - and we do not experience the problems described in their white paper - but then again we are careful to specify the exact proceedures required during wall construction - we make provisions for headboards and picture hanging - and we have an acoustic consultant that we use to inspect construction during various stages to assure compliance with the construction documents.

Shorting out with RC can happen - but once again - this is a problem with incorrect installation - and we see to it that this never happens.

Understand as well - we do not always use RC - we always construct double wall assemblies - always double layers (minimum) 5/8" drywall - and we use light guage metal framing whenever we do not require structural studs.

In the recording studio we constructed (roughly $450,000 without any equiptment or low voltage wiring - and not including the costs of the building we constructed to house it (so just room within room costs)) I did not use RC either - What I did was pay careful attention to de-couple it from the outer structure - and used a mix of 2x4 walls adjacent to 2x8 walls to create wall assemblies with differing TL values.

Tony Bongiovi designed the studio - and it was a fantastic success - in fact he's preparing to construct another identical studio in Florida as we "speak"

The movie studio I did was a different animal - a custom wall assembly i designed. With fairly stiff exterior walls and floppy interior walls. Lot and lot of mass on this assembly - with walls totaling more than 18" in thickness.

Steven Spielburg filmed in this studio and said it was the quietest he had ever worked in any where in the world.

All of this with standard construction materials - no magic beans.

Also, what do you think of the practice of gluing the second layer of sheetrock onto the first? You think it has any measurable benefit? Think its a waste of glue?

Personally I would never rely on adhesive for a 2nd layer - not even with the laminate screws - I like things firmly attached.

Whats your usual method, do you just screw the second drywall layer into the first (without screwing into the studs)?... or do you think its acceptable to just screw the second layer into the studs?

Personally, I think its bad practice to screw the second drywall layer into the studs... so I usually don't do that.

The one nice thing about gluing the second layer is that you have no exposed screws... so that lessens your spackling job.


We screw all sheets - I do not believe any one has a method for 2nd layers that uses only adhesive - and i shudder to think what happens down the road when that adhesive finally fails.

Taping of screw heads is the least difficult part of taping wall/ceilings - so I see no real benefit there.

There are two issues here:

(1) Free Space Loss, and
(2) Transferance of mechanical vibrations.

HOMASOTE is reccommended by manufacturer "White Papers" primarily for the latter reason, not the former.

Its not all about STC/TL..... It is also about mechanical vibrations...
This is VERY important in some enviroments; especially home studios where the predominant factor may be family members pounding on the walls, and floors, and ceilings. This is a particular problem if the studio is built in a basement, like mine is.


What you appear to mean by "mechanical vibrations" seems more to be flanking noise - by this i mean noise transfered through the structure itself.

This can be handled through decoupling of the individual structures (something you commented on in your 1st post).

Actual problems with mechanical equiptment can be dealt with by the installation of isolation hangers or bases - it isn't really that difficult.

People pounding on walls or ceilings is certainly not mechanical vibration - and would suggest that they are annoyed at a failure to isolate sound properly.

Figure out what the offending frequiencies are and there will be a fix available - usually low frequencies are the real problem - and these are solved by an increase of mass.

While I question the beneficiality of 24 o.c. spacing for
free space losses... I would not be as quick as you to
dismiss it. Changing the spacing does have a very real
physical affect on the structure.... in fact the effect
can be likened to the physics involved in a resilient channel....
its about modulus of elasticity... and it also involves
a change in the volume of air space behind the drywall
and between the studs.

I have yet to see a White Paper, and I've read hundreds
of them from manufacturers and university studies which
didn't specifically state in numerical tests, that 24o.c.
makes a difference. I don't know if anyones ever determined
the physic behind it all.... but thats what the white
papers say... and so thats what I stuck with in my design.


As i stated above - 24"o.c. is an industry standard - nothing unusual about it - and we use it quite often - however - there was an extensive lab study of over 280 wall assemblies completed in Canada - which indicated no great benefit of one over the other - so from my perspective 24" o.c. gives a definite cost benefit - but no real acoustic benefit. However - if your design utilizes 24" centers - it is a good design - i do not suggest otherwise.

Also, while acoustic caulk is supposed to be "non-hardening"
(or "non drying")... and thats doing it by he book... I still
see little problem with using structural adhesive, whether
it dries or not.

Sound takes the path of least resistance and it will travel
within reason through any open channel be it an open door, or an open window.. or a gap between sheetrock. You close that gap via any means whether it be with taping and spackle or with structural adhesive)... and the pressure wave finds someplace else to go.


Wrong,

The fact that you see little problem whether it dries or not doesn't mean much - once upon a time people believed the sun revolved around the earth - believing it didn't make it real.

The fact of the matter is that anything that dries out will eventually form cracks - this from the natural movement that takes place in all construction - expansion and contraction of the material is constant - and cracks create a path for sound to travel.

This is a fact - it matters not whether you believe it - the earth is not the center of the universe.

Sincerely,

Rod
 
Hey Rod, I'll let you know in about 10 years if the glue holds :-)

I used an awful lot of that stuff in the 3 studios that I have built.

Most of the time I screwed the second layer of sheetrock to the first...... but sometimes I just got lazy and glued the second layer on with PL-400..... ya know... just to pointlessly experiment.

I don't really know what the long term durability is... and I would certainly never do this on a commercial job where more was at stake.... but that PL-400 is real strong stuff... real strong... I'm pretty confidant in its long term durability (ignorance? or faith?).

I see no immediate reason why it would break-down (maybe in 30 years.... but I certainly think the lifespan is more than adequate to handle the 10 years a home studio will likely be used... or they wouldn't be sellling the stuff which is intended for structural purposes.
 
Industrial said:
I see no immediate reason why it would break-down (maybe in 30 years.... but I certainly think the lifespan is more than adequate to handle the 10 years a home studio will likely be used... or they wouldn't be sellling the stuff which is intended for structural purposes.

Only when used as intended - PL 400 is not a certified adhesive for Drywall - and there is nowhere in the world (that I know of) that has certified the installation of drywall with adhesive only.

PL400 is intended (designed) to be used with fasteners. Period - so no matter what your imagination says - your application is neither in accordance with either the manufacturer's recomendation or any applicable building code.

You're an engineer - figure it out - if there was an adhesive that would work without the need for fasteners it would sell like hotcakes - the company wouldn't be able to meet the need - so seeing as it doesn't exist - there must be a reason.


Rod
 
This thread has a lot of info in it! The attached pic shows my proposed "room in a room" wall construction. Not shown is the insulation between both stud types. Also the walls are 8 feet high. This thread also has the most mention of metal studs I've seen so far. The Certainteed bag showed the test data for their insulation and they used 24 in centers with metal studs. Pretty high STC ratings, but no frequency ranges were given. No mention was made here of the Auralex "Sheetblock" product. Have any of you tried it? Is any good?
 

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sg400 said:
This thread has a lot of info in it! The attached pic shows my proposed "room in a room" wall construction. Not shown is the insulation between both stud types. Also the walls are 8 feet high. This thread also has the most mention of metal studs I've seen so far. The Certainteed bag showed the test data for their insulation and they used 24 in centers with metal studs. Pretty high STC ratings, but no frequency ranges were given. No mention was made here of the Auralex "Sheetblock" product. Have any of you tried it? Is any good?

SG,

Can you remove the inner layer of sheetrock on the existing wall?

That will gain you some reduction. If you remove it carefully and then reinstalled it inside the bays - you may get between 6 to 10db greater reduction then they way you have it detailed now - without spending a penny more.

Another comment is that you can gain more room space - you do not need a 5 1/2" air space between the walls.

What guage metal studs are you using - and how are you handling the ceiling?

Rod
 
Thanks Rod. I can remove the inner layer of sheetrock (it's a messy job but someone has to di it). I am not sure what you mean by "reinstalled it inside the bays". Also, what would you recommend as a good distance between the walls? I am not sure what guage of metal stud I will be using as I am still in the design/investigational phase.
 
sg400 said:
Thanks Rod. I can remove the inner layer of sheetrock (it's a messy job but someone has to di it). I am not sure what you mean by "reinstalled it inside the bays". Also, what would you recommend as a good distance between the walls?

If - instead of just busting up the sheetrock to remove it - you were to cut it out flush with the inside of the studs (a sawz-all would work great for that) then you could take the pieces and place them inside the wall tight against the drywall on the other side -

Some of Industrial's adhesive is a good idea in this case - with a simple wood stop. Caulk the edges after this and install a wood strip around the edge to hold them in place.

A 1" air space would be adequate - 2" optimum. You really don't need any more than that.

Rod
 
OK. This is the room I have to work with. The inner walls are steel studs as per the recommendations on this thread as well as manuf. data. The doors will all be solid core. There is a 2 inch gap between the walls except in the "Lobby". Insulation will be applied as needed in the new wall as well as the common wall with the Control Room which was not insulated from the begining. Basically I am asking if this room has a chance of becoming a recording studio. Thanks to all who have responded in the past.
 

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Hi knightfly thanks for your input. I cannot touch the comon wall between the control room and the tracking room. It is a supporting wall between the room and the garage. I thought I could put the near-field speakers on the short wall. I was familiar with the thread you suggested.
 
"It is a supporting wall between the room and the garage" - I'm not seeing a garage, is it beside, above, or below ?

If your budget is too tight to re-engineer things to allow that wall to move (it's usually not a matter of possibility, only budget and time) then you could put nearfields on the short wall - you would need to use at least 2 inches of rockwool or equivalent on all 4 surfaces (ceiling, side walls, wall behind speakers) just to get a usable sound field (or almost) - It would probably help tonal balance and imaging to space the absorbent off the short wall by several inches.

Your comment about no frequency ranges is what prompted me to link that thread - STC values are typically only equal to TL at 500 hZ, everywhere else is a function of the construction. The arcane formula used for STC (I guess there actually IS one) is misleading for anything but voice isolation.

Here is a screen shot of Marshall-Day's freebie wall calculator (which I intend to buy the full version of, if they ever answer my emails), showing a wall with one layer of 1/2 and one of 5/8 sheet rock on each side of a 2x4 wall, using Resilient Channel on one side UNDER the sheet rock. Just for reference. Note the much lower dB values at lower freq's, and the small "dip" at around 3 kHz - if both sheets of drywall used were the same thickness, that 3 kHz "dip" would be more "pointy" at its bottom, due to identical coincidence dip caused by same thickness panels. .. Steve
 

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