Low Frequency Soundproofing

http://www.acoustiblok.com/

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.

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.

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!

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.

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.

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!

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.

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

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

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.

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

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.

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 !

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--

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

Hello from CT, KPG!!

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

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

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?

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!

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

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.

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.

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.

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.

Every up market B&B needs one of these

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

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

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