Knauf tp 416 ecose insulation.

[FDW]

haha, nice useful info hannes! that post should be a sticky! (is it already ? )

to OP: Knauf RS60 is what I have used and I have heard several people say it worked very well. If it has the "Knauf Ecose" branding on the product page I'm pretty sure that means it's Formaldehyde binder free. Mine is at least, I'm not sure if they have done this to the whole range.

As for fibres - yes you still want to wear protective gear whilst handling it, it can make your skin itch, and carcinogenic or not (I only have the information given to me by people on this forum, much of which differs) it is not the best thing to inhale the fibres, particularly long term. I have many in my bedroom which is a concern health wise for me and so I have wrapped mine in cling film on the advice of another Gearslutz user. I have researched that any plastic 1 mil or under, such as food grade cling film, is acoustically transparent. Some people might disagree but there are books published to the contrary so you be the judge. At any rate, some cling film is definitely not going to affect low end.

There has been loads of good info on here, you sometimes give the impression that you don't really want to research! good luck man. J

[Gdupproductions]

Originally Posted by Hannes_F

OK. You don't want to read the linkes threads yourself, so here comes

Absorption for dummies

Everything depends on the linear gas flow resistivity. This is how much the air is slowed down in the absorber when it flows through it.

To be more precise it is the resistance that the absorber gives when the air goes through it. Think you glide either on ice (low resistance) or on asphalt (high resistance). That would be a helpful picture (very rough).

Heavier stuff is more compressed and therefore the pores are smaller, so the gas flow resistivity is higher ... usually. Think gliding on asphalt. But this really depends on the details of the material: what is it made from, how big are the particles, which glue is used and so on. Therefore it is rather flakey to deal with density and the like ... but if you know the gas flow resistivity you don't need that any more. Two materials with same gas flow resistivity will perform nearly identical, no matter how different they look, weigh, touch etc.

There are four typical ranges of that:

1. Glass wool from the building center typically has 5000 Pa*s/m² which is equal to 5000 rayls/m. That is the same as the lighter Knauf products.
2. Then we have the 10000 rayls/m class. That would be the heavier Knauf products.
3. Then we have 16800 rayls/m which is the famous OC703 which is quite rigid and used for studios on the american market.
4. And finaly the quite compressed and heavy OC705 which is made for low bass absorption and has 45000 rayls/m.

Fine you say, file closed. We take the heavy OC705 stuff because it absorbs best in the low end.

WRONG.




Imagine you are an engineer constructing a ship. You know the motor will make much noise, so you want to block that. You need a material that will be the best sound blocker for a given depth. You make tests and find that the OC 705 (the heavy stuff) blocks best for the bass range. You market the OC705 as 'the best low end absorber'.

However what you don't care about is, how much of this low end is reflected towards the motor. It simply does not matter because the motor does not care.


Look at this picture. You see the incoming sound from left to right, and at the border to the absorber it splits into three parts (schematically):

1. The part that goes through (the transmitted part)
2. The part that is absorbed
3. The part that is reflected

The same thing happens when the sound comes out at the back of the absorber (I am making this very simple and rough, reality is much more complex).

What the engineer wants is actually to minimize the transmission. If transmission is low he says 'that is a fine absorber'. Because he does not care about the part that is reflected. Who cares if the motor hears a few decibels more of its own noise.

Now we come and hang this absorber into our studio. Suddenly the reflected part does matter! And we have a double problem:
1. We want the sound wave to be attenuated as much as possible when it travels through the absorber, because the rest of it will bounce at the wall, go back through the absorber a second time and then cause trouble in our studio.
2. But the other problem that we have is that a part of the wave is already reflected when it meets the absorber. And we want that to be small, too.

In order to understand that on an extreme example, think we compress our absorber until it is as dense as stone. It will block the sound very effectively but the reflected part messes all up --- in a studio, not necessarily for a motor housing. (Again, I am making this very simple in order to explain something since reality is much more complex if you really want to block noise - experts please don't read this too thorougly ).

Back to the absorbers: People have found that for studio use

• if your absorber is about 2" (5 cm) thick then OC705 is best for bass absorption.
• if your absorber is around 4" (10 cm) then OC 705 or 703 are good.
• if you can afford to make the absorber really thick (like 20" or 50 cm) then the 5000 rayls/m is the best.

You ask: Why bother with different thickness? Why not just use 2" of OC705 and call it a day?
Answer: The overall bass absorption that you can have with absorbers will be better with 50 cm of 5000 rayls/m than with 5 or 10 cm of the other stuff. But it comes with a price ... you need some space and the book shelf must go.

Now you can see that it is not possible to answer the question "which glass fibre product is the best for bass traps?". This is simply a question for which no answer exists, really.

What you need is this:

1. You commit to a lowest frequency that has to be absorbed
2. You commit to the maximum depth you are willing to sacrifice

and depending on these two you can find which material (which gas flow resisitivity) works best. That is what you can do with the Porous Absorption Calculator which you can find here:

Porous Absorber Calculator V1.57

Yes it is useable, and I have proven that if you use it right it absorbs down to 30 Hz. Read this:

first reflection panels density and thickness

HOWEVER

... if you are not ready for sacrifying 30 - 50 cm on each wall for this sort of treatment then you should use the light stuff only for corner traps and search for OC703 / 705 style material for the panels. Or use tuned traps etc. etc. There are many possibilities that go way beyond your question.

You really think so?

I got it . So 5000 rayls/m would only be usefull at thickness off 20 to 50cm?. What about 10000 rayls/m at 100mm ? for bass. and 5000 rayls/m at 50mm for reflection panels ?.

Ive used the calculator thing (great thing to have , but it doesn't calculate densitys with it. And from what i know the knauf ecose tp 416 has 16kg/m3 and probally 5000 rayls/m so that would only beneft high end to mids ?.

My room is only around 1.90m in width so i can make my bass traps 100mm thick and refelction 50mm.


Also i saw you and FDW mentioning food wrap plastic ?, why would you want to use that ? doesn't it block soundwaves from being absorbed ?, would polyester wadding not be a better idea ?.

I would like to follow your advise at this point, cuz i know what your talking about.

[avare]

Hannes:

Thank you for a great dummies article! thumbsup

Absorbingly,
Andre

[Hannes_F]

Originally Posted by Gdupproductions

I got it . So 5000 rayls/m would only be usefull at thickness off 20 to 50cm?.

If we are talking about bass, yes.

What about 10000 rayls/m at 100mm ?

Porous Absorpton calculator says: No significant absorption for bass lower than 150 Hz:

My room is only around 1.90m in width so i can make my bass traps 100mm thick and refelction 50mm.

In a room with 1.90 width you are lost in regards to bass if you rely on absorption only. Maybe with tuned absorbers or perforated panels, but there are others here that have more experience with that. Try to read every post of Jens Eklund, he has succeeded in makin a room flat that has 7.5 m² if I recall right.

Also i saw you and FDW mentioning food wrap plastic ?, why would you want to use that ? doesn't it block soundwaves from being absorbed ?

I used to use food wrap plastic but use even thicker plastic now. The reasoning is this:

Do I hear music through a plastic foil? Yes, especially the bass does not care. Therefore it does not matter for the bass absorption if you wrap the absorber into plastic, it does not prevent the bass waves from going into the glass fiber and to be absorbed there.

With the top end it is another story. The higher frequencies (from a few hundred Hz on) are reflected, the higher the more. That can help if you use much absorption because then you can control the low end with absorption and the high end with reflection.

Which means: Careful with plastic wrapped absorbers at your reflection points. At these places you can

• use fabric
• put acoustical foam as an additional layer on the plastic
• angle the absorbers to direct reflections away from you.

You must test the padding wrapping if you want to use it. For example I used some plastic foil from the construction center that has a felt like layer on it but it turned out that this reflects quite good in the range of 800 - 900 Hz. What I am trying to say is that if you want to know that you need own measurements.

With a room of 1.9 m width it would be an option to check the bass strictly on headphones. Unless you don't have the expertize of a Jens Eklund and others at your side I think realistically you might be tackling too big a problem ...

One not too shabby solution: Buy four traps at least 10 cm thick from GIK or Realtraps. Place the speakers near the front wall (like 5 cm distance). Place two of the absorbers at the front wall between the speakers and two at the sides. That is a 250 EUR no mess solution that you can re-use when you find a bigger room. I see many composers to have such rooms and obviously it works, and with the traps certainly better than without. It works good enough for them to have a very successful career, get awards for their work etc.. Here you see the composer Andreas Moisa that frequently writes for german TV and companies like Mercedes, BMW etc.:



Now that I look closer at it I see some nice corner traps but it is not overdone. If I were you I would start with the panels and then add such corner traps.

If you then have a bigger room to your disposal it would be a better time to buy a measurement microphone and go the DIY acoustics route.

cheers
Hannes

[Glenn Kuras]

Gdupproductions,
Sorry for the delay on getting with you. We are not going to hide what we are using (to a point) but understand we are not going to use all the same density for every product. Just like we don't use the same density now, so we need to match up things. The best I can tell you at this point is go for the 3 pound as it seems to have nice absorption on the low end and the best bang for the buck over all. I think for things like filling the corner you could use 1.6 pound with confidence.

[Gdupproductions]

Originally Posted by Glenn Kuras

Gdupproductions,
Sorry for the delay on getting with you. We are not going to hide what we are using (to a point) but understand we are not going to use all the same density for every product. Just like we don't use the same density now. The best I can tell you at this point is go for the 3 pound as it seems to have nice absorption on the low end and the best bang for the buck over all. I think for things like filling the corner you could use 1.6 pound with confidence.

Thanks glenn,
Low end- low mids and mids are a problem for me in my room so that is where im focusing at (i gues it is for everybody :P, but it gets realy muddy over therre). So i gues 3 pounds is around 48kg/m3 right ?.

[Gdupproductions]

Originally Posted by Hannes_F

If we are talking about bass, yes.

Porous Absorpton calculator says: No significant absorption for bass lower than 150 Hz:



In a room with 1.90 width you are lost in regards to bass if you rely on absorption only. Maybe with tuned absorbers or perforated panels, but there are others here that have more experience with that. Try to read every post of Jens Eklund, he has succeeded in makin a room flat that has 7.5 m² if I recall right.

I used to use food wrap plastic but use even thicker plastic now. The reasoning is this:

Do I hear music through a plastic foil? Yes, especially the bass does not care. Therefore it does not matter for the bass absorption if you wrap the absorber into plastic, it does not prevent the bass waves from going into the glass fiber and to be absorbed there.

With the top end it is another story. The higher frequencies (from a few hundred Hz on) are reflected, the higher the more. That can help if you use much absorption because then you can control the low end with absorption and the high end with reflection.

Which means: Careful with plastic wrapped absorbers at your reflection points. At these places you can

• use fabric
• put acoustical foam as an additional layer on the plastic
• angle the absorbers to direct reflections away from you.

You must test the padding wrapping if you want to use it. For example I used some plastic foil from the construction center that has a felt like layer on it but it turned out that this reflects quite good in the range of 800 - 900 Hz. What I am trying to say is that if you want to know that you need own measurements.

With a room of 1.9 m width it would be an option to check the bass strictly on headphones. Unless you don't have the expertize of a Jens Eklund and others at your side I think realistically you might be tackling too big a problem ...

One not too shabby solution: Buy four traps at least 10 cm thick from GIK or Realtraps. Place the speakers near the front wall (like 5 cm distance). Place two of the absorbers at the front wall between the speakers and two at the sides. That is a 250 EUR no mess solution that you can re-use when you find a bigger room. I see many composers to have such rooms and obviously it works, and with the traps certainly better than without. It works good enough for them to have a very successful career, get awards for their work etc.. Here you see the composer Andreas Moisa that frequently writes for german TV and companies like Mercedes, BMW etc.:



Now that I look closer at it I see some nice corner traps but it is not overdone. If I were you I would start with the panels and then add such corner traps.

If you then have a bigger room to your disposal it would be a better time to buy a measurement microphone and go the DIY acoustics route.

cheers
Hannes

Im willing to build 4 thick bass traps (140mm) to place in front corners and left/right reflection point. While i don't wanna treat my back wall cuz that's wherre my bed is located i tought off building a very thick maybe 6 inch ? bass trap to place right behind my back....( my speakers are in axis so anyhow dricket sound will hit the absorbe behind me).

Here is a drawing;....(if needed i can upload actualy picture,s 2).

PS; the book case will be covered with velour carpet (so it isnt 100% refelctive dunno if it makes any sense).

[Glenn Kuras]

Originally Posted by Gdupproductions

Thanks glenn,
Low end- low mids and mids are a problem for me in my room so that is where im focusing at (i gues it is for everybody :P, but it gets realy muddy over therre). So i gues 3 pounds is around 48kg/m3 right ?.

Yes!!

[Gdupproductions]

Originally Posted by Glenn Kuras

Yes!!

Glenn, . aren't you looking at the knauf acoustical boards ?
cuz they seem to have attractive numbers don't they

Knauf Acoustical Board Smooth with ECOSE® Technology

3 inches seem to slap.

[Glenn Kuras]

I have been looking at it all weekend.

[Brainchild]

Of course, you could get good low-frequency results using a very high-resistivity material - and you wouldn't need very much of it at all - as long as you have the free space to put behind it and don't mind a little rippling.

[Gdupproductions]

Originally Posted by Glenn Kuras

I have been looking at it all weekend.

Now is the question; where getting it ?. Ive been looking on google but it seems there are no companys carrying these....anyhow ive contacted knauf about this.

[Glenn Kuras]

Originally Posted by Gdupproductions

Now is the question; where getting it ?. Ive been looking on google but it seems there are no companys carrying these....anyhow ive contacted knauf about this.

In your neck of the woods I have no idea. I do know we will have to buy pretty big quantities ourselves (if we go this route).

[Jens Eklund]

Originally Posted by Brainchild

Of course, you could get good low-frequency results using a very high-resistivity material - and you wouldn't need very much of it at all - as long as you have the free space to put behind it and don't mind a little rippling.

"The flow resistivity values used to derive the dimensionless term X, must fall within the range: 1,000 < s < 50,000 rayls m-1"

[Amioa]

the insulation board as available in the US is not available in the UK or europe, only the Knauf materials made in europe, which are not the same(or weren't last time we looked)

I'll get a couple of photos of the UK and US materials side by side so you can see the difference, i'll post them tomorrow if i can work out how.

[Gdupproductions]

Originally Posted by Amioa

the insulation board as available in the US is not available in the UK or europe, only the Knauf materials made in europe, which are not the same(or weren't last time we looked)

I'll get a couple of photos of the UK and US materials side by side so you can see the difference, i'll post them tomorrow if i can work out how.

So i gues only thing for me to do is grab any knauf product with ecose that has 10.000 rayls/m and make the best out off it ?.

[Glenn Kuras]

Originally Posted by Gdupproductions

So i gues only thing for me to do is grab any knauf product with ecose that has 10.000 rayls/m and make the best out off it ?.

Yes.. In your area mineral wool ecose based is what you would want.

[Amioa]

Still hunting for uk knauf sample, it's here somewhere.....it's interesting to see the difference between the 2 materials, 1 is rockwool, the other is fibreglass. It seems to be a bit more flackey too

[Gdupproductions]

Originally Posted by Amioa

Still hunting for uk knauf sample, it's here somewhere.....it's interesting to see the difference between the 2 materials, 1 is rockwool, the other is fibreglass. It seems to be a bit more flackey too

Rockwool ugh.....give me rigid fiberglass anytime.

[musikmaschine]

I recently somewhat rashly bought some Knauf dritherm cavity slabs. I thought they were rigid but they aren't, they are like semi rigid fibreglass panels ans will need covering.

So should they have absorptive properties? From what i've read here they should but i don't know, there's no acoustic information on them. It looks similar to the other stuff mentioned in this thread so i think it may and according to Hannes' guide it should (thanks, makes things a lot clearer).

If not is there anything i can do with them? I have no cavity walls to fill! The panels are 100mm thick and are fairly dense.

Cheers!

[avare]

Originally Posted by musikmaschine

I recently somewhat rashly bought some Knauf dritherm cavity slabs. I thought they were rigid but they aren't, they are like semi rigid fibreglass panels ans will need covering.

So should they have absorptive properties? From what i've read here they should but i don't know, there's no acoustic information on them. It looks similar to the other stuff mentioned in this thread so i think it may and according to Hannes' guide it should (thanks, makes things a lot clearer).

If not is there anything i can do with them? I have no cavity walls to fill! The panels are 100mm thick and are fairly dense.

Looking at the website, the material has water repellents in it. These may close the interstices of the mineral wool. This would make it not an acoustic absorber.

Andre

[musikmaschine]

Originally Posted by avare

Looking at the website, the material has water repellents in it. These may close the interstices of the mineral wool. This would make it not an acoustic absorber.

Andre

Thanks. I'll see what i can find out next week. This stuff has been used in a diy build which is why i bought it: - View topic - DIY Broadband Absorbers / Acoustic Panels

I should have done more research into the acoustic properties but i didn't realize there were so many different types of knauf insulation. I thought by it's very nature it was absorptive.

[takman]

is anyone using the knauf ultra acoustic P for bass traps/panels?


Boards ULTRACOUSTIC P for partition walls | Knauf Insulation Greece

im trying to find out more information about it....such as gas flow resistance...