3 interesting materials with data- which to choose ?

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3 interesting materials with data- which to choose ?

Postby Cornelius » Mon Jul 30, 2007 11:25 pm

Hi,

I am stuck and therefore I need some other opinions. I want to build some new "standard"  absorbers (4" thick)  without fiberglass / rockwool ( I know It's not really toxic or a cancerogen, but I want to use "ecological" material  :8 ).

I have done some research and in my opinion the following materials looks promising.

FlexCL.
(cellulose )http://www.homatherm.com/uk
Image

~70 kg/m³
flow resistivity:43 - 76 kPas/m²  (rayls/m)
(more detailed)
Image

measured absorption for 2" (5 cm)
(measured in an "echo chamber")

125 | 0.2
250 | 0,80
500 | 1
1000 | 1
2000 | 1
4000 | 1

(the whole report with diagramms unfortunately only in German)
http://www.homatherm.com/fileadmin/medi ... flexcl.pdf

HolzFlex
http://www.homatherm.com/uk (wood fibre)
Image

~40 kg/m³
flow resistivity:  9-16 kPas/m²

measured absorption for ~3" (8 cm)
(impedance tube not "echo chamber", I think therefore not really comparable? )

125 | 0.11
250 | 0.27
500 | 0.67
1000 | 0.95
2000 | 0.93

(the whole report with diagramms)
http://www.homatherm.com/fileadmin/medi ... lzflex.pdf

Thermo-Hanf
(hemp)
Image

~38 kg/m³
flow resistivity:  6 kPas/m²

measured absorption for ~1.6" (4 cm)
(measured in an "echo chamber")

125 | 0.20
250 | 0.45
500 | 0.70
1000 | 0.85
2000 | 0.90
4000 | 0.95

(the whole report with diagramms )
http://www.thermo-hanf.de/upload/pdf/Schall.pdf

I really don't know which material I should choose. FlexCL looks very good, but as far as I know the flow resistivityis a bit too high ( grazing incidence - http://forum.studiotips.com/viewtopic.php?t=2254) and the famous "Porous Absorber Calculator" says the same if you do some tests. But it's cellulose and not rockwool/fiberglass, maybe this material has different characteristics?

HolzFlex has a flow resistivity similar to OC703, but the measurement doesn't look that good. Maybe wood fibre is not that good for sound absorption?

Thermo-Hanf has a bit to low flow resistivity for my taste, but the measurement looks ok. There are also absorption data for 6" in the detailed report which looks good too.

At the moment I would choose FlexCL for a standard 4" absorber, but it would be great if I could hear some other opinions.

Thanks and if there are open questions please ask.  :wink:
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Postby bert stoltenborg » Tue Jul 31, 2007 10:30 am

Ein recht schoenen guten Tag.
:D

I'm by far not the best to answer this, but I'm with you in your choise.
These latter two materials seem a bit lightweight. But Eric, Terry, Joel, Jeff  or Scott know everything about this.
:D
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Postby Scott R. Foster » Tue Jul 31, 2007 11:09 am

Not me... but the latter two do seem a bit low in density for 100mm wall panels [might make good SuperChunks though].

I would look for some +/- 6 to 8 lbs rockwool panels and compare prices versus the cellulose boards listed.  

Don't kid yourself... there is nothing inherently ecological about making insulation from plant fiber [grown, harvested, shredded, bleached and spun into fiber] versus sand [dug up, melted and spun into fibers].  The lower cost of mineral fiber likely reflects in part a lower energy expenditure in its collection and fabrication into a suitable form to make the panels.
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Postby Eric.Desart » Tue Jul 31, 2007 2:04 pm

:mrgreen:  Rockwool has even something useful from an historical point of view
In fact most of this stuff is lava stone (basalt, diabas, etc.).  By digging that out we maybe can find very old cultures back.

I do agree with Scott: I don't see what's less ecological about mineral wool.

More to the point:

These boards look maybe promising but that tube measurement doesn't look that well.  Normally when translated to reverb room measurements the results will be better, mainly in the lows.
The measured density is 56 kg/m3.  This means for wood with an initial density about 3 times lower than stone, that possibly there is more thicker fiber, hence a much smaller cell surface, which could explain a lower absorption.
But I'm gambling a bit.

I find it easier to judge when having samples in my hands.

That 160 mm board is a damned nice curve.
That lab is know to be very good.  That's more a research institute also selling measurement stuff.

Best regards
Eric
.

PS: I once did some acoustic work for a huge bottle factory.
Within a couple of kms of my home there is an old fortress where they store these bottles collected by our recycling methods.
That become huge mountains of glass bottles.
I asked that bottle factory about this. Why don't you use all that glass? It feels that we're not recycling but creating new mountains as it is now.
He told that they have to heat that glass to higher temperature (more energy), that cleaning all that stuff and sorting calls for another significant amount of energy, and then I don't speak about all the energy needed in the collection, sorting, transport procedures.  Hence, back then when I asked about this, even when they got the stuff for free they weren't that happy about it.
And one could say: it's all about profit.  And probably it is. But if significant more energy is needed than that's an ecological minus, going hand in hand with this profit stuff.

I am FOR recycling and saving our world for future generations.  I do mean that.
But I also believe that a lot of this recycling is more, or at least a lot of symbolic stuff than really ecological.
.
Last edited by Eric.Desart on Tue Jul 31, 2007 2:52 pm, edited 1 time in total.
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Postby Cornelius » Tue Jul 31, 2007 2:50 pm

Thanks for your answers guys, they really helped me out.  

You may be right in relation to ecological reasons, I'm not an expert in this area,  but I think I will build some test absorber with this FlexCL stuff anyhow. I am just a curious person and I can get some of this stuff for cheap ...   :wink:

regards
c.

ps:

But I also believe that a lot of this recycling is more, or at least a lot of symbolic stuff than really ecological.


Sad but true..
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Postby Rod Gervais » Tue Jul 31, 2007 3:56 pm

Cornelius wrote:
But I also believe that a lot of this recycling is more, or at least a lot of symbolic stuff than really ecological.


Sad but true..


Of course it's true (and I don't think it's sad either) - it's a marketing ploy to capture the attenion of the green movement - and they are quite a large market....

Otherwise - if they were only a small share of the purchasing public this product wouldn't exist -

In the end - green isn't  about the ecology (which I believe is doing just fine thank you very much)  it is all about getting rich - making money - filliing up those bank accounts...............

which is exactly the way it should be- that's what business is all about.......... find a market niche and fill it.........

sincerely

Rod
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Postby bert stoltenborg » Tue Jul 31, 2007 4:03 pm

:mrgreen:
Hey Rod, tell us about global warming...
:mrgreen:
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Postby Bob » Tue Jul 31, 2007 6:14 pm

Rod Gervais

which is exactly the way it should be
That's debateable. Capitalism at its core is amoral and sociopathic. Capitalism is a good thing. Amoral and Sociopathic are bad. Privately held companies can be ethical, but some have said that due to their responsibility to shareholders to make the largest proffit possible that publicly held companies must, by law, be unethical. Up to an Enron point of course.

Then of course there's the definition of 'green' -- a whole other debate of which you've volunteered but one point.
Regards
Bob Golds
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Postby Rod Gervais » Wed Aug 01, 2007 2:57 pm

Bob wrote:Rod Gervais

which is exactly the way it should be
That's debateable. Capitalism at its core is amoral and sociopathic. Capitalism is a good thing. Amoral and Sociopathic are bad. Privately held companies can be ethical, but some have said that due to their responsibility to shareholders to make the largest proffit possible that publicly held companies must, by law, be unethical. Up to an Enron point of course.

Then of course there's the definition of 'green' -- a whole other debate of which you've volunteered but one point.


Bob,

I don't want to start a flame war here - so let's keep this friendly........   :wink:

I am a conservationalist - but view some other segments of the "green movement" as eco-freaks..........

I would have no problem throwing some jerk in jai for the rest of his life who dumped chemicals on his property that then contaminaated mine -

BUT - I don't have a problem with "Killing trees" in order to build buildings - or to use to furninsh the inside of studios designed like Power Station.

I think that the green movent goes way overboard iia lot of cases - for example - back in the day when I was first learning construction - we would deliberately design and consruct buildings so that the air infiltration rate was one complete air exchange per hour - this through the subtle use of cracks along the joints between the foundation and base plate of the building - through the use of cracks along doors and windows - the cracks around electrical boxes, etc.

And then the eco-freaks began screaming about all of the wasted energy that was escaping from houses because of this "sloppy workmanship" (note that I said this was by design - not by mistake) and the energy cops began requiring us to tighten things up.

SO now - in the states - you have LEEDS standards (U.S. Green Building Council’s Leadership in Energy and Environmental Design) which you have to meet in order to even bid on certain projects -

Their standards for air infiltration require a maximum air exchange of .3 air changes per hour.

And then what do they have to do ? They have to pump in ((via fans (extra electrical costs)) and treat (same costs as before) fresh air into these buildings (including the high end residential units being built to their standards) fresh air because the building are getting sick air syndrome.

SO where we were doing it as a part of the building design - they now have to add duct and fans (additional electrical costs long term - never mind the costs related for upkeep) to acheive the same tings were were dong for free....... (remember that the heating/cooling costs remain the same regardless of where the fresh air comes from).

To me this is insane.

IN the US we had (back in the good old days) Nuclear Breeder plants - to which we would send spent  power rods so that they could be regenerated - after which they could be sent back to the reactor plants to be reused - and this (of course0 could be repeated to the point that nearly 100% of radioactive materials were spent in the life of  their power fgeneration.

The product remaining after the final use was (for all intent and purpose)  inert - and could be dumped just about anywhere without creating problems.

BUt - after scraming about the dangers of nuclear power  by the  eco-freaks  the federal govt outlawed breeder facilities - so not we have a stockpile of spent energy rods that have to be dealt withi in some manner - and these do have concentrated  radioactive loads that can create leathal situations if a problem arises.

I do have a problem with the fact that (in the states) a bever can put up a dam on the brook that runs through my property - but I can't take it down because it would disrupt the ecology  _ BUT - I can't get a permit to put up the same dam because  it would disrupt the ecology....... I do know a farmer in Connecticut who lodst his strawberry fields in hisorchards because of a bevears dam - and they could not care less that his property was made useless  - it was a bever after all - and they had rights too.........

I am aware of the fact (note I said fact) that there doesn't exist ANY natural renewable energy sources which (if taken in large enough amounts to provide anything other than miniscule amounts of energy) ) we won't pay some ecological penalty for (that includes sun - air and water energies).  

As far as global warming and the ozone layer goes - we only discovered the ozone in the early fifties - and could only begin measuring it in the 70's - and yet - with only gathering 30+  years of data on something that has existed for hundreds of millions of years 9we have convinced ourselves) that this small amount of data is conclusive enough for us to  develope real computer models that represent reality?

That's akin to taking one reading with a microphone in a room and  developing all of our room treatments from it. And then never testing again - because after all - we had that one reading.

There is no way that 30+ years of data can prove conclusively that anything out of the ordinary exists.........  hell - for all we know - the ozone could naturally open up for thousand year cycles - and then close up for another thousand year cycle......

Beside which - even supposing that global warming was real - and assuming that the polar caps melted - the cries of flooding out the world are over stated to say the least -

Seeing as the only addition to the water levels would be that which sits above sea level - the most increase you would see would be somewhere in the range of a 6" rise in sea level world wide........   nothing suggesting that suddenly we loose all of our existing sea front.........  or any of it for that matter.........

And predictions (once again) of what would happen from the perspective of changing weather patterns is questionable - again because we don't have enough statistical data gathered to really program computer models which come to meaningful data -

remember -  you can set up a computer mdel to conclude whatever you want it to - that doesn't men the conclusion is meaningful.

With all sincerity..........

Rod
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Postby Bob » Wed Aug 01, 2007 4:01 pm

Rod:

I don't want to start a flame war here
Yep. While I doubt that you and I could get into one, I think we could spawn one without too much trouble.  :bang

I agree with a lot of that post. Certainly all first 2/3, to which you are known to be an expert.  :8

after scraming about the dangers of nuclear power  by the  eco-freaks  the federal govt outlawed breeder facilities
I think it was Jimmy Carter (president USA) who outlawed them, mostly because of the plutonium -- more 'war dangerous' than 'eco dangerous', so perhaps 'eco freaks' isn't the right word. To get to eco-freaks I'd have to go a little further out of occam's razor to politics around the time of Three Mile Island. Ecofreaks would have given their supporting votes after that decision was made though, so it's part of the picture.

BTW, it's "beaver".   :mrgreen:  (National Animal of Canada -- so we learned to spell it a lot)
The attached is an urban legend, based on a true story from years earlier.
(recall that to view PDF's from this website, you may have to use Save Target As and open it from there)
Attachments
Dam.pdf
Dam
(69.9 KiB) Downloaded 160 times
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Postby bert stoltenborg » Wed Aug 01, 2007 4:05 pm

Good story, Rod.

You cannot even model a room adequately, let alone a climate you don't understand 1% of.
But every electronics chain is now promoting we should load our houses with eco tv's, cd-players and electrocars.
And some crazy secretary of state over here wants penalties for people using light bulbs, we only are allowed to use these saving bulbs. The industry is laughing it's ass off.
And even some banks over here have green credit cards.
All based on creating fear by unsustained science and agressive media campains.
Makes me sick to my stomach.

This Al Gore is just a hippie in disguise.

:mrgreen:
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Postby Rod Gervais » Wed Aug 01, 2007 4:37 pm

Bob wrote:BTW, it's "beaver".   :mrgreen:  (National Animal of Canada -- so we learned to spell it a lot)
The attached is an urban legend, based on a true story from years earlier.
(recall that to view PDF's from this website, you may have to use Save Target As and open it from there)


Bob,

thanks for the spelling correction - I needed that..........   :lol:

On to the letter -

That was a riot - and on the right property I can see myself writing that very same letter.........  thanks for sharing it

Sincerely,

Rod
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Postby Rod Gervais » Wed Aug 01, 2007 4:39 pm

bert stoltenborg wrote:This Al Gore is just a hippie in disguise.



Bert,

if I said Al  Gore was a moron - I would be paying him a complement..........  he really isn't that bright..........

Sincerely,

Rod
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Postby jcgriggs23 » Wed Aug 01, 2007 6:07 pm

Rod,

I agree with you about eco-extremists (I've yet to meet an anything-extremist who made any sense to me), but your statement about "only having 30+ years of data" regarding atmospheric gasses is just wrong - we can accurately measure gas levels all the way back into prehistory via ice cores.  There is now a world-wide scientific concensus on all but the most fine details of global warming.  Whether you agree with it or not, I think that any reasonable person has to question the sanity of messing with a dynamic system on the scale of the global climate...

My $0.02 (Canadian),
  John
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Postby bert stoltenborg » Wed Aug 01, 2007 7:26 pm

:D
I like! Highfive! Let's do this quickly, before the Belg tells us to concentrate on acoustics!

You can look in the past using ice cores, but that's not exactly a fine method.
And scienctist aren't clear about what you see. Does CO2 determine heating, or is it a delayed effect following heating?
Untill now it's not even clear if there is any ice melting or if indeed it is growing.
Antartica seems to get colder, and I read a report (serieus science) tellling that greenland is melting at the edges and getting thicker at the middle, like it is married a couple of years ago.
And we don't understand the enventual influence of the sun, etc etc etc.
We cannot measure sealevels when we don't understand the dynamics of our earthcrust.
We cannot even get consensus about if the atmosphere is heating up.  

Of course we should take care, but we don't.
You in North America spill more energy than anybody, and we in the old world are only trying to get pass you. And then this Oriental block coming up, you think they will cut down on their economy.

I'm sick of hearing morons tell me that I should turn the light out in the loo while they are taking a plain to a conference where they can score cheap hookers and eat and drink 'mselves to death, spilling an amount of energy in the proces I could burn my toilet light on for 15.000 years (we calculated that   :mrgreen: ).
I don't want to hear I should drive less fast and at more contant speed and then being forced to accelerate and decelerate every 50 meters because they pave every road with traffic bumps and roundabouts.
I hate fashion, especially when it's stupid fashion and a lot of idiots that decided to govern us don't even know they are talking fashion.

You know: Stop global warming! Stop continental drift!

Lets do a hippie jam festival, that'll teach 'm!

:mrgreen:  :mrgreen:
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Postby bert stoltenborg » Wed Aug 01, 2007 7:34 pm

Oh, we already did the hippie jam festival. They calculated the total CO2 emission of that. But screw it, a load of artists will see their income grow so they can buy porsches or ferarri's. Or Hummers!
:mrgreen:
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Postby bert stoltenborg » Wed Aug 01, 2007 7:38 pm

Or all of 'm.
If you view life with the knowledge that there are no problems, only opportunities, you are a marketing manager.......this is my personal philosophy
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Postby Eric.Desart » Thu Aug 02, 2007 1:27 am

bert stoltenborg wrote::mrgreen:
Hey Rod, tell us about global warming...
:mrgreen:


It did work again/once more didn't it?
:twisted:  Please I want to talk about and question this stuff I'm against (covers about anyone and anything), but give me the handle to hide behind.
Image
divinely-inspired
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Postby Ido » Thu Aug 02, 2007 7:35 am

as often here, bottom line, you all seem to be to me saying the same basic things, and I agree to them all.
what this world lacks, and we have (I'm serious) is the combo of common sense, intuition and logic, with some shreds of humanity and decency, and, getting priorities right.
so is Scott running for president or not?
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Postby bert stoltenborg » Thu Aug 02, 2007 10:00 am

Eric.Desart wrote:
bert stoltenborg wrote::mrgreen:
Hey Rod, tell us about global warming...
:mrgreen:


It did work again/once more didn't it?
:twisted:  Please I want to talk about and question this stuff I'm against (covers about anyone and anything), but give me the handle to hide behind.


:D
There's more in life than absorption.
I like to hear how people in other parts of the world think about disturbing stuff.
If you view life with the knowledge that there are no problems, only opportunities, you are a marketing manager.......this is my personal philosophy
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