CR4 - The Engineer's Place for News and Discussion®

Previous in Forum: Business School Doctrine Kills Innovation in the US   Next in Forum: Megahertz Frequency and Heat to Electricity
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







29 comments
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2

Low Frequency Soundproofing

11/29/2011 6:51 AM

I am a Cape Town architect with a sound reduction problem. Further to a discussion last year titled "Anyone Have experience with Low Frequency Soundproofing?", does anyone have knowledge of an American product called Acoustiblok, which is claimed to have unique properties - comparable to sheet-lead - for reducing low frequency air-borne traffic noise. If Ted White reads this, his technical knowledge seems excellent, and I would be particularly interested in his input.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 4646
Good Answers: 229
#1

Re: Low Frequency Soundproofing

11/29/2011 7:14 AM
__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#2
In reply to #1

Re: Low Frequency Soundproofing

11/29/2011 7:38 AM

Hi ozzb, I know the website, but thanks anyway. I am after independent info from anyone who has possibly used the product, or is familiar with it.

Register to Reply
Guru
Hobbies - Automotive Performance - New Member Popular Science - Weaponology - New Member

Join Date: Oct 2008
Location: Want to be: 34° 34' 21.60" N, 92° 55' 42.28" W Really am in Arizona
Posts: 29650
Good Answers: 1114
#3
In reply to #2

Re: Low Frequency Soundproofing

11/29/2011 8:00 AM

I've never used this stuff, but I'm skeptical after looking over their web site. Their explanation of "how it works" is a little suspect. And, I'll bet it's pricey, too.

Unless they can produce attenuation data from 10 Hz to 15,000 Hz don't go near it." In speech range 4000 Hz test results indicated a 14 DB reduction (which represents over 60% reduction in noise to the human ear)" 14 dB at 4,000 Hz is not difficult to do. What can it do at 30-90Hz?????

The lower the frequency, the longer the wave length, the more density, or distance, it takes to attenuate the sound. We need to know more about your specific problem.Don't place the order, yet.

OOPS, I'm not Ted White. Please disregard.

__________________
Luck comes and goes. Skill is forever. The supply of fools will always outstrip the demand .
Register to Reply
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#4
In reply to #3

Re: Low Frequency Soundproofing

11/29/2011 8:52 AM

Hi Lyn, the problem is a 120-year-old cottage at the bottom of a steep hill, used by large trucks. The place is now an up-market B&B. External walls are corrugated iron on studs, with internal t&g boarding. I doubt there's anything in the cavity. I'm aware windows are as problematic as walls, and 'split' aircon will also be required. The floor is timber on joists, so a heavy additional skin is out of the question. This light-weight product has only recently been introduced in this country, but as a suspicious sceptic myself, no ordering of anything without compelling endorsements!

Register to Reply
Guru
Hobbies - Automotive Performance - New Member Popular Science - Weaponology - New Member

Join Date: Oct 2008
Location: Want to be: 34° 34' 21.60" N, 92° 55' 42.28" W Really am in Arizona
Posts: 29650
Good Answers: 1114
#6
In reply to #4

Re: Low Frequency Soundproofing

11/29/2011 9:24 AM

Oh boy. That's a tough one. I assume you want to retain the outer and inner walls as they are now? I don't suppose you want to apply the sound insulation material to the outside of the corrigated iron?

Can you plant tree, or some type of dense shrub, to act as a barrier?

Then first, I'd fill the internal spaces with insulation. Attic, too. Next, you're faced with removing the outer iron and installing some type of sound deadening material underneath it.

Depending on the amount of money you have and how big the space is you want to treat, you might consider some type of active noise cancellation system, or maskiing (white) noise.

There may be others here who can add to my meager offerings.

If all else fails hire an acoustics expert who can come on site and evaluate your specific problems.

__________________
Luck comes and goes. Skill is forever. The supply of fools will always outstrip the demand .
Register to Reply Score 1 for Good Answer
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#7
In reply to #6

Re: Low Frequency Soundproofing

11/29/2011 10:52 AM

Hi Lyn, outer corr. iron must be retained. Only15" from boundary fence, covered with thick hedge (no acoustic help at all!). Intended to replace inner skin, fill cavity with something and put Acoustiblok behind new drywall. Forget 'white' noise. When a truck revs up or changes gear, white, grey or pink noise serves no purpose! (I'm reasonably OK on sound-proofing, having designed a professional sound studio in a residential area. With speakers churning out 120db, no apparent sound 15ft from the building. All empirical decisions, since I'm no expert). You know the definition of 'expert'? Ex is has-been, spurt is a drip under pressure! Acoustiblok video shows jack-hammer noise reduced to zero, insulated by a layer of their product. Impressive, but what frequency is a jack-hammer? I'm still hoping to hear from someone with first-hand experience of Acoustiblok.

Register to Reply
Guru
Hobbies - Automotive Performance - New Member Popular Science - Weaponology - New Member

Join Date: Oct 2008
Location: Want to be: 34° 34' 21.60" N, 92° 55' 42.28" W Really am in Arizona
Posts: 29650
Good Answers: 1114
#8
In reply to #7

Re: Low Frequency Soundproofing

11/29/2011 12:38 PM

Yes, well the more transitions the wave sees the better the effect.

You might even consider using narrow 1x2 inch strips, on edge, to space the drywall out from the sound material. This would give you one more dead air space to kill more of the sound.

I can't find anything in the Acoustiblok web site that inpresses me.

(My acoustics experience is with mostly active noise cancellation systems so we didn't need any physical deadening materials.)

Good luck!

__________________
Luck comes and goes. Skill is forever. The supply of fools will always outstrip the demand .
Register to Reply
Guru
Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member

Join Date: Apr 2009
Location: USA, Florida
Posts: 1191
Good Answers: 107
#10
In reply to #7

Re: Low Frequency Soundproofing

11/29/2011 3:54 PM

What frequency is a jack-hammer?

What frequency is a large truck on a hill ?

When the frequency gets low enough, it cannot be stopped by anything except noise cancelling technology. Low frequency waves can be (and are) transmitted hundreds of miles through the earth as a means of communicating with clandestine operations. Low frequency noise is omni-directional and will pass through anything. The product you are considering may very well stop much of the noise, but when it comes to low frequencies, the difference between them and impact concussions are few.

__________________
An obstacle is something you see when you take your eyes off the goal.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Dec 2005
Location: Etats Unis
Posts: 1860
Good Answers: 46
#13
In reply to #3

Re: Low Frequency Soundproofing

11/29/2011 11:40 PM

The trick is, they don't specify at what frequency the amazing results exist.

__________________
The hardest thing to overcome, is not knowing that you don't know.
Register to Reply
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 4646
Good Answers: 229
#5
In reply to #2

Re: Low Frequency Soundproofing

11/29/2011 8:58 AM

Like me some of us may not be that familiar with the product. Everyday should be a learning experience! So the link was for them. With that knowledge soneone may be able to point to alternatives to help you out.

hey I was there easy copy and paste

__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply
Guru
Hobbies - DIY Welding - New Member, but planning to be an Old Member Popular Science - Weaponology - New Member United States - US - Statue of Liberty - 56 Year Member

Join Date: Apr 2009
Location: Cowboy Capitol of America
Posts: 5886
Good Answers: 231
#9

Re: Low Frequency Soundproofing

11/29/2011 1:39 PM

Anechoic materials.

This list of Google hits may provide some direction... your description of the problem makes me think it will probably be a series of small fixes, each of these contributing a little bit to an overall positive and desired outcome.

This is a tough one.

__________________
Semper Ubi Sub Ubi
Register to Reply
Guru
Hobbies - CNC - New Member Popular Science - Biology - New Member Hobbies - Musician - New Member

Join Date: Dec 2008
Location: Canada
Posts: 2767
Good Answers: 128
#11

Re: Low Frequency Soundproofing

11/29/2011 6:34 PM

There's a metamaterials design which looks interesting, but I don't think it's made it to market yet. Thin and effective.

__________________
incus opella
Register to Reply
Guru
United States - Member - New Member Engineering Fields - Mechanical Engineering - New Member Engineering Fields - Petroleum Engineering - New Member Hobbies - Target Shooting - New Member

Join Date: Jan 2008
Location: Spring, Texas
Posts: 3410
Good Answers: 148
#12

Re: Low Frequency Soundproofing

11/29/2011 10:46 PM

I've had very good luck with these guys: http://www.earsc.com/

They manufacture the stuff used for anechoic tiles for submarines as well as all sorts of other sound and vibration damping materials. they even make RAM sheeting for stealth aircraft. I would suggest sheets of their viscoelastic polyurethane stuck to the inside surface of the corrugated steel sheet to prevent it from acting as a sounding board for the sound. combined with fiberglass batting. further i'd put a second mechanically separate set of studs between the existing studs offset by an inch or so so that the inner wall and the outer wall are mounted to separate studs.

__________________
Who is John Galt?
Register to Reply
Power-User

Join Date: Apr 2007
Location: New york
Posts: 139
Good Answers: 6
#14

Re: Low Frequency Soundproofing

11/29/2011 11:48 PM

I admit I must know more about the details of the project, but I will explain one thing about low frequency. To block or absorb low frequency you need to do more than you have to with higher frequencies, that can be absorbed with fiberglass and mineral wool, all having to do with density. Low frequency absorption necessitates "bass traps", where in order to fully absorb low frequency you need more overall depth, varying densities, and space in between. So there's not much one can do with a two inch gap and 40 db of 40 Hz.

[p]I want to give credit to Lyn because sometimes you have to address the situation on multiple fronts, and dealing with a problem at the source is a great sign of intelligence.

[p]If you cannot control the source volume, then you must use a balance of absorption and soundproofing techniques. You can contact me if you want to chat about it, feel free. I personally "float" rooms to isolate them from outside noise (and vice versa). If floating is not an option I do use different layered systems of varying densities to harness the low end situation. Within these layers I use rubber layers but all strategically put together in a sequence. Also, keep in mind, you must use the right caulk (NOT JUST ANY) to create completely solid layers.

[p]Can't go into more than that now, send pics and good luck !

__________________
In such a vast universe, I can only bask in my own insignificance....
Register to Reply
Power-User

Join Date: Jun 2008
Posts: 427
Good Answers: 17
#15

Re: Low Frequency Soundproofing

11/29/2011 11:55 PM

There is acoustic sheet rock being made, there are sites that deal with the Boom-Box cars, that load up their interiors with the most sound-deadening material you can think of--I am in building, and there is a new product , I believe , called Green Glue, which is a caulk used to adhere another layer of drywall right over the existing drywall, or plaster, that is supposed to dampen sound very well, with a little fuss. I have built Sound Studios, and have used everything from sheet lead, to Mass Vinyl, to sound board, drywall multiple layers of each etc--Often the sound comes from the ground--Unless you cut the concrete, to isolate the surrounding ground mass, then cut the wall studs, and isolate the walls from the floor, add new bottom plates, and then use rubberized floor support systems to support the walls, I am afraid you will have to find out WHERE your noise is originating--The Sound Engineers we use bring in the Oscilloscopes , microphones, and other remote frequency sensing devices, and start from there--A trip to Radio Shack may give a source of some low cost measuring devices--The Hz of frequencies you mention have readily available sources for material that address those frequencies-Good luck and let us know what works--

Register to Reply
Active Contributor

Join Date: Mar 2011
Location: South Africa
Posts: 19
#16

Re: Low Frequency Soundproofing

11/30/2011 2:29 AM

Howzit Dave.

There's a company in Joburg that sells this. (http://www.able.co.za/)

Give them a ring - they might send you a sample to play with.

It costs about R600/square.

I wanted to line the inside of a small 12V motor housing with it but turned out to be too thick and heavy for our application. (also it seems to work better when its free standing).

Good luck

KPG

__________________
ditto
Register to Reply
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#17
In reply to #16

Re: Low Frequency Soundproofing

11/30/2011 2:43 AM

Hello from CT, KPG!!

I'm in contact with the company. I was just hoping for some independent opinions or endorsements!!!

Register to Reply
Active Contributor

Join Date: Mar 2011
Location: South Africa
Posts: 19
#18
In reply to #17

Re: Low Frequency Soundproofing

11/30/2011 3:07 AM

ha! how'z the mountain bru?

ok, but back to the topic.

My general feeling was that it can work nicely for certain applications but you need to choose your application wisely.

Also I think you'll be able to get away cheaper (the classic scenario of sitting in a bar having a chat to an old acoustic buddy and after bragging about your latest find he replies: "but you know that if you soak cotton wool in molten bees wax...")

but sorry I don't really know enough for a proper contribution.

__________________
ditto
Register to Reply Off Topic (Score 5)
Associate

Join Date: Jun 2009
Location: Minneapolis, MN
Posts: 41
Good Answers: 5
#19

Re: Low Frequency Soundproofing

11/30/2011 5:46 AM

I've used SONEX panels. http://www.pinta-acoustic.com/

__________________
There's ALWAYS another plan.
Register to Reply
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 3301
Good Answers: 89
#20

Re: Low Frequency Soundproofing

11/30/2011 6:36 AM

Traffic rumble propagates through the ground and into anything attached to it. That includes the air above the ground and around everything else that is vibrating with it.

You have a fence with foliage on it already to attenuate the air propagated sound and you still hear the low frequency traffic sound. The wall is not the problem.

Short of sitting your cottage on some sort of damping or isolating system I don't think you can deal with this passively.

Noise cancellation? Maybe better but no guarantees either. So many variables?

Have you asked the Acoustiblok vendor if there are any sites near you where the product has been installed so you can go and have a listen for yourself?

How have your neighbours dealt with the problem?

__________________
Difficulty is not an obstacle it is merely an attribute.
Register to Reply
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#21
In reply to #20

Re: Low Frequency Soundproofing

11/30/2011 7:49 AM

Hi Wal,

Not traffic 'rumble' at all. Actual truck engine noise about 15' from the wall!! Some reasonable sound attenuation is all I'm after. However as you say, the variables and impossibility to predict results are major problems. I still believe noise comes through the wall, but I also know windows - in side walls not facing the street - would need replacement and split aircon installed - all v expensive!! The product hasn't yet been used in Cape Town and the only agent is in Johannesburg, over 1000 miles away! Neighbours don't need to deal with the problem. Modern construction here is double-skin cavity brickwork. Even internal walls are usually brick. My client just happens to own an historic remnant - charming, but fraught with problems!

Register to Reply
Power-User

Join Date: Oct 2007
Location: Canning Vale Western Australia.
Posts: 153
Good Answers: 7
#22
In reply to #21

Re: Low Frequency Soundproofing

11/30/2011 8:40 AM

I know you may be looking for a solid brick but this was on a local inventors programme in Australia a few years ago. Hope it helps

http://www.scienceinpublic.com/freshinnovators/2004/chrisfield/chrisfield.htm

__________________
I attend work so my dogs can have the good life.
Register to Reply
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 3301
Good Answers: 89
#24
In reply to #21

Re: Low Frequency Soundproofing

12/02/2011 3:47 AM

Convince your client that any attempt to sound proof the structure will impact on its charm.

The restoration should not remove any characteristic traits that are typical to the structure's genre.

Excellent noise transmission is what makes it a tin shack. It's a treasure worthy of preservation without change.

__________________
Difficulty is not an obstacle it is merely an attribute.
Register to Reply
Active Contributor

Join Date: Jul 2010
Location: Midland, Michigan
Posts: 10
#23

Re: Low Frequency Soundproofing

12/01/2011 1:42 PM

Acoustiblock is one of dozens of trade names for the same material: Mass Loaded Vinyl. Essentially PVC mass-loaded with Calcium Silicate. They used to use Barium.

MLV, regardless of the name, is simply a source of mass. Weighs 1 pound per square foot. Cost is $1 a square foot. 5/8" drywall is 2.2 pounds psf and costs $0.22 a square foot. So over twice the mass for 1/5 the cost. It's also easier to work with than MLV.

Where MLV and drywall differ is that drywall can conduct a vibration better and drywall has a resonance frequency (coincidence point). Neither of these points is germane if using a damping compound like the Green Glue previously mentioned.

MLV was much more popular years ago when competent damping compounds were not available. MLV continues to hand on in the marketplace because it's the most profitable soundproofing material a dealer can sell. Sad truth.

Register to Reply
Active Contributor

Join Date: Nov 2011
Posts: 24
Good Answers: 2
#28
In reply to #23

Re: Low Frequency Soundproofing

12/04/2011 7:14 PM

Hi Ted

Thanks a ton! You've given me precisely the info I needed. I will go the damping compound route, and it certainly will be Green Glue, depending on landed cost here. I'll investigate further.

Register to Reply
Commentator
Hobbies - Fishing - New Member

Join Date: Jul 2007
Location: Cape Town, South Africa
Posts: 59
#25

Re: Low Frequency Soundproofing

12/04/2011 3:44 AM

Hi Dave

Maybe this is worth a try. It is designed to keep sound inside motor vehicles, but perhaps it will work the other way around.

There is a company here in Cape Town that stocks it.

__________________
Do it while you still can!!
Register to Reply
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 3301
Good Answers: 89
#26

Re: Low Frequency Soundproofing

12/04/2011 4:05 AM

Every up market B&B needs one of these

http://www.youtube.com/watch?v=g1eUIK9CihA

__________________
Difficulty is not an obstacle it is merely an attribute.
Register to Reply
Guru
United States - Member - New Member Engineering Fields - Mechanical Engineering - New Member Engineering Fields - Petroleum Engineering - New Member Hobbies - Target Shooting - New Member

Join Date: Jan 2008
Location: Spring, Texas
Posts: 3410
Good Answers: 148
#27

Re: Low Frequency Soundproofing

12/04/2011 11:27 AM

have you considered low expansion foam in place isocyanate insulation in the wall cavities?

__________________
Who is John Galt?
Register to Reply
Participant

Join Date: Sep 2013
Posts: 1
#29

Re: Low Frequency Soundproofing

09/22/2013 4:07 PM

Hi, wanted to know what you used after all, im in cape town and busy trying to soundproof a bar. did you use the green glue, and what was the cost

Register to Reply
Register to Reply 29 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

artsmith (1); C-Mac (1); csoulpro (1); d_entrepreneur (1); daveh (6); dhotel2000 (1); Doggoneit (1); Doorman (1); KPG (2); lyn (3); MauriceS (1); ozzb (2); rcapper (1); Rorschach (2); Ted White (1); Wal (3); WJMFIRE (1)

Previous in Forum: Business School Doctrine Kills Innovation in the US   Next in Forum: Megahertz Frequency and Heat to Electricity

Advertisement