John Sayers' Recording Studio Design Forum Archive

Soundman2020 wrote:Once again, we get back to the original question that you have not yet answered: WHY DO YOU THINK THAT YOU NEED TO FLOAT YOUR FLOOR?

There are very, very few valid reasons for doing that. None of them apply to your case!

We keep in telling you that you do NOT need to float the floor, and the only reason you have given is that "I've seen it done in other places". That's not a valid reason for doing it in YOUR place.

So please answer the question: What is the technical, acoustic reason for floating your floor?

You don't seem to have any reason at all for doing that. Doing it right is complicated, expensive, slow, and very hard to get right, plus it uses up room height.

Did you read this document?

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

After reading that, please explain the technical reason why you want to float your floor.


- Stuart -

Yes i've read the document, more that once. It is all clear to me but when i went to this company the guys there told me that making a drum riser with rockwool-plywood-2ply gypsumboard-plywood "sandwich" or a floor like that it is a good, efficient and affordable solution but i had to take into consideration the disadvantage of rocwool's compressive stress over the years. Thats why they proposed me the solution with the pads which will offer natural frequency reduction till 4Hz plus there is no need to poor concrete over them and i wont have to worry for compressive stress of them over the years

beeros05 wrote: Thats why they proposed me the solution with the pads which will offer natural frequency reduction till 4Hz plus there is no need to poor concrete over them and i wont have to worry for compressive stress of them over the years

You will not ever, in my life time get a 4Hz natural frequency from wood unless it is like 15 Meters thick:)

It is not going to happen, it is just not going to happen...heck, with a floating concrete floor...it would take 10 (help me out here Stuart) inches +/- to achieve that.

xSpace wrote: You will not ever, in my life time get a 4Hz natural frequency from wood unless it is like 15 Meters thick:)

It is not going to happen, it is just not going to happen...heck, with a floating concrete floor...it would take 10 (help me out here Stuart) inches +/- to achieve that.

Mate, i really appreciate your concern and Stuart's and that's why i keep posting here with you guys, because your opinion is important for me. I don't doubt you or dispute you about the floor but once the manufacturer proposed this solution why not to try? If it does not work i will return the pads and get my money back. This company manufactures these products guys. I really do not believe they would risk to lie to me for their products. There is good fame on the market for their products here in Greece plus the cost was not huge, it was 220€ for the pads.

I think you should also take in consideration that there is different architecture/manufacture of Greek buildings are not similar to US buildings. The concrete foundations/slabs are all "connected" with all the concrete columns/rebars of the whole building. Most of the buildings in US ets are not made from ONE slab and on top gypsumboards. The building is full of concrete and rebars.

Let me try to understand this: You are taking the word of a salesman who really wants to sell you his product, even though his specifications defy the laws of physics, and you are NOT taking the word of people who really don't care what you do, are not trying to sell you anything, and are just trying to give you good advice? Is that it? And you are doing this after you already got burned by another guy who wanted to sell you his services, even though his specifications also defied the laws of physics, and you ended up having to tear it all down and start again?

Like Brien said: There is no way on this planet that you can get 4Hz isolation with huge, and I mean HUGE amounts of mass: Just take a look at the equations for resonance. They are not complicated, and a simple calculator will show you that what this guy promises you is impossible.

The very best isolated studio in the world is Galaxy Studios, located in Belgium. Their design spec is very similar to what your salesman claims. The natural resonance of their isolation system is set to 3 Hz. But in order to achieve that, they had to do things a bit different from what your salesman is telling you. The control room floor at Galaxy weighs over two hundred and fifty tons! It is supported on 78 specially designed helical steel springs. The entire studio weighs over two THOUSAND tons, and it cost them many, many millions of dollars to build it.

So please, I think you'll forgive me for laughing when some salesman in Greece says he can do the same job for 200 Euros with a bag of rubber pads!!!!

This is what a studio floor spring system looks like when it is tuned to 3 Hz:
(Copyright note: I'm not sure, but I believe this photo originally came from Studiotips web site, and in any event it belongs to Eric Desart, who designed those springs).


But this salesman guy goes even better! He not only says that his Euro 200 bag of rubber pads will do the same as Galaxy (3 Hz), but that it will give "frequency reduction till 4Hz", which implies resonance of TWO Hz. (to isolate at a certain frequency, the resonance of the system must be half of that frequency, or less)! So this guy thinks he can get isolation twice as good as 250 tons of concrete on million-dollar custom designed helical steel springs with elastomer damping, and he can do that on thin rubber pads WITHOUT any mass on top? And you believe him?

BRIEN:

it would take 10 (help me out here Stuart) inches +/- to achieve that.

Let's see now... Concrete density is around 2300 kg/m3, so you'd need about one hundred cubic meters of concrete to get to 230 tons. The room we are talking about has a floor area of about 12 square meters, so you'd only need to make that floor about 8.3 meters thick.... Wait, let me check: 8.3 x 3.5 x 3.4 = 98.88 cubic meters, x 2300 kg/m3 = 227 metric tons. Yup. I got it right.

Hmmmm, I have a feeling the room isn't tall enough to fit that floor in....


Brien told you last time, so I'll tell you this time: You have been taken. Fooled. Had. Conned. Scammed. Fortunately, it was only 200 Euros this time, not 6,000 like last time, but the result is the same.

There's not too many things that make me angry on-line, but such obvious scams are one of them!

I'll give you one last piece of advice: Turn around, run, and get as far away as you can from that guy. Who knows what else he'll try to dump on you, now that he got you to buy into his first hoax. Maybe he'll be telling you about this bridge he has in New York, that he can sell you, real cheap....

I really do not believe they would risk to lie to me for their products.

Tell you what: Send an e-mail to Eric Desart, and ask him about that. Eric is the guy who designed Galaxy, and did the calculations for those giant springs with massive concrete floors. He's one of the most respected acousticians in the world, and he even posts here on this forum sometimes, so his e-mail address and PM access are available to you. Just send him a message, and ask him if he agrees that rubber pads without any mass on top can isolate a room down to 4 Hz.

Or send an e-mail to any of the other world-class professional studio designers here on the forum, such as Glenn, Andre, Rod or John himself, and as if they agree that rubber pads with no mass can isolate a floor down to 4 Hz.

I guarantee you that you will NOT find anyone to support that notion, since the claims made by your salesman defy the laws of physics.

I think you should also take in consideration that there is different architecture/manufacture of Greek buildings are not similar to US buildings

Perhaps, but the laws of physics and acoustics are the same, everywhere in the entire universe. It doesn't matter if you live in the USA, Chile or Greece, the universal laws that govern how the universe works are the same everywhere, including the laws of acoustics. And those laws make it absolutely, totally, and entirely impossible to float a low-mass studio floor on thin rubber pads and achieve isolation down to 4 Hz.

The concrete foundations/slabs are all "connected" with all the concrete columns/rebars of the whole building.

Just like where I live! That's how we build things here, because of the earthquakes. Chile has suffered the largest earthquake ever recorded, plus several others on the "top ten" list, so we learned the hard way how to build structures that can withstand that. So yes, concrete and rebar buildings are rather common here. And when I was involved in the construction of one of the top studios in Santiago many years ago, which they built on the SECOND floor (not ground floor) of such a building, they floated it with massive amounts of concrete on resilient supports. And it cost them a fortune. Maybe I should call them up and ask them if they would like to replace all that with a bag full of 200 dollar rubber pads, and some sheets of plywood...

Construction doesn't matter: the laws of physics matter. The equations and formula matter. There is no construction technique, or construction material, that can change the laws of physics. Sound and vibration work exactly the same here where I live, as they do where you live, and where Brien lives. Anyone who tries to tell you different is a liar, plain and simple. Using concrete and rebar doesn't change anything (and I'm pretty sure that Brien understands concrete and rebar even better than I do!). Sound still behaves the same.

The point is, what you NEED for your room is NOT million dollar floating floor springs, and certainly not a 200 Euro bag of rubber pads, but isolation. Isolation is achieved by mass, by tuning, and by decoupling. The main issue is NOT your floor: it is your DOOR, and you haven't even mentioned what you plan to do about that. The next major problem is your WALLS and CEILING (they go together). Then after that you biggest problem is your HVAC system (ventilation): And only then, in last place, is your floor. It is the least important of all, since it is a concrete slab sitting on top of the ground. So it already has lots of mass, and it already has lots of damping (the dirt underneath). It is already isolating well.

So let me clarify: The problem with concrete-and-rebar construction is flanking noise, not air-borne noise. The problem is things that impact (bang into) the floor. There is a large amount of mass in the concrete, so souns that are in the air CANNOT make it vibrate. The ONLY thing that can make it vibrate, is direct impact. The way to stop impact noise from getting into the floor, is NOT to float the entire floor: that isn't even the purpose for floating a floor. The solution is simply to decouple. That just means to stop things form hitting it! Very, very simple. That's what a drum riser does: it decoupled the drum kit form the floor. It is NOT a floating floor, and doesn't pretend to be one. It is NOT a resonant system, and in fact is designed to resonate as little as possible, and at a relatively high frequency, NOT a low one. It simply stops the drum kit from touching the floor, and absorbs the impact.

I showed you one way of building one very cheaply, based on mineral wool, and the only objection that your "expert" salesman had to that plan, was that you might have to replace the mineral wool in five or ten years! So big deal: if you are still using that room ten years from now, and you start noticing that the mineral wool needs replacing, then go to your local hardware store, spend a few euros (but a lot less than 200!), and buy some new mineral wool. And that's assuming that this supposed "compressive stress" that affects Greek mineral wool happens to strike yours! But it is rather curios that your salesman would mention something about "compressive stress in mineral wool", when I never even suggested mineral wool for building your drum riser: I specifically told you to use OC-703, which is NOT mineral wool. So there are only two possibilities: either your salesman doesn't have a clue what OC-703 is, or he does know and just pretended to be ignorant, so he could lie to you...

Or if you really cant stand the thought that you might have to spend a few euros on new mineral wool (or OC-703) in ten years, then don't build it that way! There are MANY ways of building drum risers. You could probably build a great one using Sorbothane for the decoupling, or EPDM, or neoprene, or several other possibilities.

But anyway, if you insist on floating your floor, even after reading IR-802 (which I gave you links to several times), then I think you'll be on your own as far as I'm concerned. So all I can say, is good luck with your build.

- Stuart -

Edited to add: I just looked at the web site for those pads: the guy was NOT telling the truth to you when he said you didn't need concrete for them. Read what their very own website says:

"It can be placed under the metal supports of machinery or under concrete floating inertia supports, in single or multiple layers.": Only two options here: You can use those pads to float heavy machinery OR you can use them to float CONCRETE inertial supports.

It doesn't say anything at all about using them to float a drum kit....

Did you READ the specs? Did you understand the table that shows you what load factors you need to apply in order to make it float? Did you read what these things are meant for?

Here, I'll paste it for you:

SUITABLE FOR LARGE LOADS
APPLICATIONS
ANTIVIBRATION SUPPORTS:
Air-compressors - Air conditioning units – Pumps – Fans – Generator sets – Cutting machines etc.
FLOATING SUPPORTS:
Industrial floors – Elevators – Printing machines – Testing machines etc.

do you


Do you see any place there where is says you can use them to float a sheet of plywood with a drum kit on top? These things are design for "LARGE LOADS"! Read it again. Do you have any idea how much a large generator or printing press weighs? Do you know that an "industrial floor" is? Here's a hint: it is not a sheet of plywood with a drum kit on top!

Plain and simple: the salesman lied to you if he said that you don't need any mass. Their very own web site proves that. Just like with all heavy-duty resonant isolation systems, you need a LOT of mass if you want that to work. And the salesman also misrepresented what the web site said about isolating down to 4 Hz. Read it again, and see if you can figure out how he misinformed you there, too....

In other words, I'm sure the products work as advertised, but what they salesman told you is very, very different from what the web site says....

Soundman2020 wrote:Let me try to understand this: You are taking the word of a salesman who really wants to sell you his product, even though his specifications defy the laws of physics, and you are NOT taking the word of people who really don't care what you do, are not trying to sell you anything, and are just trying to give you good advice? Is that it? And you are doing this after you already got burned by another guy who wanted to sell you his services, even though his specifications also defied the laws of physics, and you ended up having to tear it all down and start again?

If i would not take your words guys i would not post here. I do take your word because you saved my ass and my pocket! And i REALLY appreciate it! But we must place in order some things in order to communicate better because we are dealing with scientific terminology and maybe i haven't understood something right or i have not expressed something right.

I am trying to tell you that "this guy" is not just a salesman, he is the manufacturer of these products. He just proposed me the pads to properly decouple my drums from the floor. Now according the specs of these pads the weight "sandwich" on top is setting them in charging state and they start behaving as spring. As far as the 4hz (it is 7 Basically) Isolation YES it seems to me impossible as well, probably i understood something wrong. Please check the Specs PDF of the product. It is the RED PAD 6cm x 6cm dimensions (The last one on the "VIBRO EP SELECTION TABLE")

Soundman2020 wrote: So please, I think you'll forgive me for laughing when some salesman in Greece says he can do the same job for 200 Euros with a bag of rubber pads!!!!

No hard feelings...

Soundman2020 wrote: Brien told you last time, so I'll tell you this time: You have been taken. Fooled. Had. Conned. Scammed. Fortunately, it was only 200 Euros this time, not 6,000 like last time, but the result is the same.

There's not too many things that make me angry on-line, but such obvious scams are one of them!

Mate do not get upset please, i got really frustrated with the gypsumboard technician, i still am basically so i really do not worry at all for the rubber pads, i told you before it is very easy to return them and get my money back, the floor is the last thing i worry about!

Soundman2020 wrote:Send an e-mail to Eric Desart, and ask him about that. Eric is the guy who designed Galaxy, and did the calculations for those giant springs with massive concrete floors. He's one of the most respected acousticians in the world, and he even posts here on this forum sometimes, so his e-mail address and PM access are available to you. Just send him a message, and ask him if he agrees that rubber pads without any mass on top can isolate a room down to 4 Hz.

I already have done that, i sent him a pm through the forum

Soundman2020 wrote:The main issue is NOT your floor: it is your DOOR, and you haven't even mentioned what you plan to do about that.

Stuart my problem as you mention below is flanking-impact noise, I don't have problem with airborn noise, i really dont. And i have mentioned what will i do with the door, 2 doors with triplex laminated glass, you got so frustrated that you forgot!

Soundman2020 wrote: The next major problem is your WALLS and CEILING (they go together).

Here is the drawing he gave me for walls and ceiling
https://lh4.googleusercontent.com/-Y_Ez ... DESIGN.jpg

Soundman2020 wrote: Then after that you biggest problem is your HVAC system (ventilation)

Ι do not have enough space to properly isolate the hvac system, the only thing i can do is to use "isolated" tubes (dont know how are they called in English)

Soundman2020 wrote: I showed you one way of building one very cheaply, based on mineral wool, and the only objection that your "expert" salesman had to that plan, was that you might have to replace the mineral wool in five or ten years! So big deal: if you are still using that room ten years from now, and you start noticing that the mineral wool needs replacing, then go to your local hardware store, spend a few euros (but a lot less than 200!), and buy some new mineral wool. And that's assuming that this supposed "compressive stress" that affects Greek mineral wool happens to strike yours! But it is rather curios that your salesman would mention something about "compressive stress in mineral wool", when I never even suggested mineral wool for building your drum riser: I specifically told you to use OC-703, which is NOT mineral wool. So there are only two possibilities: either your salesman doesn't have a clue what OC-703 is, or he does know and just pretended to be ignorant, so he could lie to you...

Stuart you never proposed my a specific material like OC-703 as far as i can tell, we were talking about drum risers made by these types of materials but not something specific, also in Greece we do not have OC 703, i can find glasswool but not the specific one because what contractors use here for insulation is rockwool. Any way i got the point...

Soundman2020 wrote:You could probably build a great one using Sorbothane for the decoupling, or EPDM, or neoprene, or several other possibilities.

Stuart the pads i bought are neoprene pads and a bought the for 2.5€ per piece approximately

Soundman2020 wrote: But anyway, if you insist on floating your floor, even after reading IR-802 (which I gave you links to several times), then I think you'll be on your own as far as I'm concerned. So all I can say, is good luck with your build.

Stu i read the document, i got the idea and it was really hard to understand the document due to the terminology, i am not that fluent in this part. I appreciate what you do but please take in consideration that you are a scientist (as far as i understood structural engineer and "enthousiast self tought" acousticologist[?] ) which means that the fact that is "easy" for you to read and understand these kind of documents. You have also studied in a University and you have working experience. I am not the same, i am a waiter and hobbyist drummer...I cannot comprehend some terms as you do It is not easy i get lost!!! And i also got the difference i am not trying to float my floor, i am just decoupling it.

Any way...thank you for your time i will forward the thread to the manufacturer right now

Stuart you never proposed my a specific material like OC-703 as far as i can tell, we were talking about drum risers made by these types of materials but not something specific,

Right here, paragraph 13:

http://www.johnlsayers.com/phpBB2/viewt ... 63&start=7

Here's the paragraph:

For drums, there's a much better idea than trying to float your entire floor: just float the drums! You do that with something called a "drum riser", that is basically just a floated platform inside the room, that you set up your drums on. It is easy and cheap to make, and works very well. It properly isolates your drum kit from the floor, and you can build it simply with common construction materials. It can be something simple like a 10cm layer of semi-rigid fiberglass insulation (such as OC-703) put directly on the floor, and two sheets of 15mm plywood screwed together, lying on top of the insulation. That makes a good drum riser. You can also make a frame for it, and do other things to make it better. There are plans and diagrams of how to build drum risers, right here on the forum.

He just proposed me the pads to properly decouple my drums from the floor.

Then I'm confused once again, because things keep on changing here! Are you trying to float your FLOOR, your ROOM or just your DRUMS? There's a huge difference. What exactly did you tell this salesman you are trying to do, and what exactly did he propose? Because with each post it seems like there's something new... So if all you want to do is to float your drums, then why do you need 220 Euros worth of pads at 2.5 Euro each? This isn't making sense...

Now according the specs of these pads the weight "sandwich" on top is setting them in charging state and they start behaving as spring.

And how much weight do you calculate that you need? And for what amount of surface area?

As far as the 4hz (it is 7 Basically) Isolation YES it seems to me impossible as well, probably i understood something wrong. Please check the Specs PDF of the product. It is the RED PAD 6cm x 6cm dimensions (The last one on the "VIBRO EP SELECTION TABLE")

That's exactly the part I quoted form in my last post, where I told you that I'm sure the pads work as advertised, but that they will not do what you say they told you. But now you are saying something else! So what exactly DID they tell you? What you said that the told you is that you don't need any mass to get 4 Hz natural resonance. That is plain WRONG, since the specs for the product say the exact opposite. You need MASS. If you are going to use around 90 of those pads You say they cost 2.50 each, and you paid 220 for them) then you need a LOT of mass, just like the laws of physics say, and just like the manufacturer's web site says, but that's NOT what you claim the salesman told you...

Here is the drawing he gave me for walls and ceiling

Ummm..... and that drawing CLEARLY SHOWS that you need CONCRETE! The title even says "floating concrete floor"!!!! So you are telling me that the salesman gave you that drawing, that clearly shows you need the concrete slab, then told you that the drawing is wrong and that you don't need concrete?????

You said that they told you that "there is no need to poor concrete over them", but the drawing they gave you shows very thick concrete, and so does the title. So I don't get it: Did they tell you that you do NOT need concrete (mass) on your floor, or did they tell you that you DO need concrete (mass) on the floor? If they told you that you do need it, which is what their diagram shows, then why did you tell us here that they told you you don't need it? Here I am, saying that they told you lies, when in fact the drawing they gave you shows that they told you the truth!

The drawing looks fine, by the way: but what you said that they told you is NOT fine. That's what is so confusing here. What they show in the drawing is, indeed, a good way of isolating a room. But is DOES show that you need mass, just like Brien said and just like I've been trying to tell you.

First you say "These pads under the weight of the wood are taking the amount of pressure that is needed in order to float according to his calculations." then you show a drawing with very thick concrete, not wood!

I don't have problem with airborn noise, i really dont.

Then why are you specifying those isolation walls? If your ONLY problem is impact noise flanking out of the room, and there's no problem with airborne, then what's the purpose of two layers of drywall on isolation-mounts, with insulation in the cavity? And what's the purpose of the ceiling on isolation mounts?

Ι do not have enough space to properly isolate the hvac system, the only thing i can do is to use "isolated" tubes

You don't need much space for that. Silencers don't take up much room. And if you don't isolate the HVAC system, then everything else you do is not going to help much: sound will simply escape via the HVAC.


- Stuart -

Right here, paragraph 13:
http://www.johnlsayers.com/phpBB2/viewt ... 63&start=7
Here's the paragraph: For drums, there's a much better idea than trying to float your entire floor: just float the drums! You do that with something called a "drum riser", that is basically just a floated platform inside the room, that you set up your drums on. It is easy and cheap to make, and works very well. It properly isolates your drum kit from the floor, and you can build it simply with common construction materials. It can be something simple like a 10cm layer of semi-rigid fiberglass insulation (such as OC-703) put directly on the floor, and two sheets of 15mm plywood screwed together, lying on top of the insulation. That makes a good drum riser. You can also make a frame for it, and do other things to make it better. There are plans and diagrams of how to build drum risers, right here on the forum.

I probably missed that...

Then I'm confused once again, because things keep on changing here! Are you trying to float your FLOOR, your ROOM or just your DRUMS? There's a huge difference. What exactly did you tell this salesman you are trying to do, and what exactly did he propose? Because with each post it seems like there's something new... So if all you want to do is to float your drums, then why do you need 220 Euros worth of pads at 2.5 Euro each? This isn't making sense...

A floating floor needs mass i got that its ok. The purpose is to have a more "proper" decoupling floor. He proposed me to put double pads 2 layers of 50 pads on the surface. He told me to put more pads where i would put the drum-kit and my drum-throne because of the extra weight of the kit and myself, and when i would be ready he would tell me exactly were i should place the pads

And how much weight do you calculate that you need? And for what amount of surface area?

He made the calculations for the weight of the sandwich and me. I don't know yet what is the exact weight of my drum-kit
I am 90+ kilos, so he explained me that the general rule to place more pads in certain areas were my body weight "falls". This would be exactly calculated when it was the time to make the floor.

I need approximately 5 double layer pads for every m2 for the whole surface, but under the drum-kit's surface (including me) the placement of the pads would be different.

What you said that the told you is that you don't need any mass to get 4 Hz natural resonance. That is plain WRONG, since the specs for the product say the exact opposite. You need MASS. If you are going to use around 90 of those pads You say they cost 2.50 each, and you paid 220 for them) then you need a LOT of mass, just like the laws of physics say, and just like the manufacturer's web site says, but that's NOT what you claim the salesman told you...

The salesman told me that the weight/mass of the sandwich (without concrete) is enough to make the pads behaving as springs and he also proposed me to make the dual layer to reduce the natural frequency down to 4 from 7Hz. I translate his exact words the best way i can. Is it clear enough? He didn't mention "isolation of natural frequency" He said "it is better to use 2 layer pads to reduce the natural frequency". And i also wondered for the weight and i asked him "Won't i need more weight on top since i will have 2 layer pads?" And he said that "the the pressure limits remain the same, 2 layer pads affect in the reduction of natural frequency"
Ok, these where his exact words!
Man it is awfully stressful this situation...i mean sometimes i wish would never have begun it.

Ummm..... and that drawing CLEARLY SHOWS that you need CONCRETE! The title even says "floating concrete floor"!!!! So you are telling me that the salesman gave you that drawing, that clearly shows you need the concrete slab, then told you that the drawing is wrong and that you don't need concrete?????

You said that they told you that "there is no need to poor concrete over them", but the drawing they gave you shows very thick concrete, and so does the title. So I don't get it: Did they tell you that you do NOT need concrete (mass) on your floor, or did they tell you that you DO need concrete (mass) on the floor? If they told you that you do need it, which is what their diagram shows, then why did you tell us here that they told you you don't need it? Here I am, saying that they told you lies, when in fact the drawing they gave you shows that they told you the truth!

Stuart I showed you the drawing that i will follow for the walls and the ceiling. Ouf course it is my fault that i didn't mention that
the pads that are shown to the drawing are thicker model (the blue) and bigger (12.5x12.5cm) for heavier constructions Basically the Blue pad in the drawing needs 6 times more load -than the red pads that i have- in order to start acting like a spring. as well that i will not use soundbar between the gypsum-boards. Sorry...Foolish!

Then why are you specifying those isolation walls? If your ONLY problem is impact noise flanking out of the room, and there's no problem with airborne, then what's the purpose of two layers of drywall on isolation-mounts, with insulation in the cavity?

Stuart, the main problem is impact noise. I don't say that there is no airborne noise annoying but it is not the big problem. When i play in the afternoon my neighbors hear me but there is the city noise outside so i am not annoying them that much. Besides it is winter now and everybody has closed windows, i believe in summer i will be annoying them a lot if i don't make walls. But the big problem is the vibrations being transferred to the ground-floor and the first floor. They cant watch TV...

And what's the purpose of the ceiling on isolation mounts?

Decoupling?

You don't need much space for that. Silencers don't take up much room. And if you don't isolate the HVAC system, then everything else you do is not going to help much: sound will simply escape via the HVAC.

Silencers are placed outside the room right? I have to put the tubes in a "box" with insulation and the tube must be in a "snake form" right? I dont have much space...
My apologies for any inconvenience in my previous posts regarding the saleseman and me. I am 100% sure for all my statements in this post. It must be the stress...

Spiros

Did you READ the specs? Did you understand the table that shows you what load factors you need to apply in order to make it float? Did you read what these things are meant for?

Here, I'll paste it for you:

SUITABLE FOR LARGE LOADS
APPLICATIONS
ANTIVIBRATION SUPPORTS:
Air-compressors - Air conditioning units – Pumps – Fans – Generator sets – Cutting machines etc.
FLOATING SUPPORTS:
Industrial floors – Elevators – Printing machines – Testing machines etc.

do you

Do you see any place there where is says you can use them to float a sheet of plywood with a drum kit on top? These things are design for "LARGE LOADS"! Read it again. Do you have any idea how much a large generator or printing press weighs? Do you know that an "industrial floor" is? Here's a hint: it is not a sheet of plywood with a drum kit on top!

Did you see the comparison chart between the pads? I have obviously caused a misunderstanding here so it is good for me to make things clear...

I have RED COLOR 6x6 not the same other colors and dimensions it needs much less load

"so you'd only need to make that floor about 8.3 meters thick."

So I got the wood wrong and the concrete wrong as well. Thanks for your participation, Talking across three different countries is always a challenge for me:)

Dear all,

Please allow me to introduce myself. My name is Antonios and I am working in the technical department of ALPHA ACOUSTIKI Ltd in Greece.

I have read comments on the forum quite a few times in the past and it is great that forums like this exist, but sadly never had the chance to join. We value and respect the free exchange of information, opinions and comments over the internet, so that is why I am taking advantage of this opportunity.

We received an inquiry by a very friendly guy (known on this forum as beeros05) regarding a «drum room» in Athens, Greece about a week ago. Being primarily a noise & vibration Consultancy Company, our first suggestion is always to visit the premises, conduct a preliminary study which would match the requirements of the specific location and as Soundman2020 correctly suggested examine the whole project as a system, rather than as individual parts. i.e. study the existing structure of the building, the HVAC parameters (primarily the ventilation system), examine the potential noise receivers, the exact source-path-receiver process and finally be able to suggest an accurate solution via an acoustic study. At this point we were informed by beeros05 that he has already received a vast number of acoustic study quotations by other acoustic consultancy firms, which unfortunately he could not afford and decided to proceed with a DIY method, which is absolutely respected. As a result the room was constructed by a local technician and you all know the results….All the mistakes were correctly highlighted by members of the forum, so there is no need to discuss further.

We were also notified that the same dry wall installer would reconstruct the space, provided he is given appropriate noise and vibration control materials and that is when we came in the picture, purely as material suppliers, known in the market for numerous successful turnkey applications in the past.

Considering all the above input received by beeros05, we conducted a meeting in our office aiming in guiding him towards the best possible solution considering the available budget and avoiding possible mistakes at the construction stage.

Let us get more technical regarding the products suggested, its specifications and application.
In Beeros05 case the below structure was suggested based on techno-economical parameters. Despite the limited budget, we try to fit the Room in Room requirements in this construction, more specifically:
http://www.alphacoustic.com/Category.asp?ID=75

1) Floating ceiling was proposed to be supported with spring hanger isolators http://www.vibro.gr/new/prod_en.php?idpr=340
which can achieve a natural frequency of 3 Hz at maximum load. We also propose to use multiple layers of gypsumborads, plus a layer of viscoelastic materialhttp://www.alphacoustic.com/Product.asp?ID=56 with mass 5 kg/m2 and fill the air gap between the ceiling and false ceiling with sound absorbing material. Airborne noise is not the main issue, but can potentially cause complaints, which need to be avoided to a maximum, as we are talking about a domestic area of Athens.

2) We propose walls to be constructed with multiple layers of gypsumboard + a layer of viscoelastic material and all floating wallshttp://www.vibro.gr/new/catalogsub_en.php?idsub=152 to be vibration isolated with appropriate rubber pads.
The principal is to prevent structure-borne noise transmission and avoid bridges throughout the whole dry wall construction. Since the «drum room» will be situated in a basement (high moisture levels are expected), VIBRO-WS would also prevent uprising moisture (capillary phenomena). All the gaps must be sealed with elastic mastic or similar products.

3) Let us now discuss about the antivibration floor system that was suggested.
We are aware that mineral wool is often used as a mean of flooring vibration isolation. Being in the field for almost 30 years now, we are unsure of the rebound capabilities of mineral wool and also long term creep behavior, especially when it is loaded by variable loads over the years. Hence, from our side we cannot suggest it as a certified vibration isolation solution. We believe that using a 50 mm neoprene pad will increase the deflection and secure a long lasting vibration isolation system that will not have to be replaced 5 or 10 years down the track.
The proposed neoprene padshttp://www.vibro.gr/new/prod_en.php?idpr=326 can achieve natural frequency with 50mm (double layer) pad around 7 Hz at maximum load. Hence allow me to say that 3Hz is next to impossible, especially when we are talking about rubber mounts (and not springs). I believe beeros05 must have misunderstood or misread the technical specifications provided. The dynamic characteristics of the floating floor with the certified sound insulation certificate according to ISO 140 & ISO 717 can be found on the following link:
http://www.vibro.gr/new/dyn/UserFiles/F ... omplex.jpg

Ln,w (normalized weighted impact sound index) is measured (in lab) to be 43dB.

Also:
http://www.vibro.gr/new/dyn/UserFiles/F ... 20blue.pdf
Overall, provided beeros05 given budget, we believe that the above suggested structure is the most adequate. Nevertheless, we would be happy to receive your feedback and discuss ideas, comments and ways of constructing «room in a room method». The above is obviously an approach that will only deliver an adequate result, provided certified technicians and installers are used. The final result in Beeros05 project will be highly dependent on the skills and experience of the onsite installer. Let’s just wait and see how the technician will go on his second chance this time around…
Similar constructions have been undertaken in the past and the results are such, that we can propose this method for room in room constructions, even for drum kits.

Once again, thank you for giving me the opportunity to share my ideas with you and looking forward to receiving your comments.

PS: I will be overseas for the next 10 days commencing on the 7th of March so please accept my apologies for any late responses.

Kind Regards
On behalf of ALPHA ACOUSTIKI Ltd

Antonios ARGOUDELIS
B. Eng Industrial Engineering
M. Sc. Environmental and Architectural Acoustics
M. Sc. Construction Project Management (U.T. Sydney)

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http://www.alphacoustic.com
http://www.vibro.gr
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ALPHA ACOUSTIKI Ltd
19, Kampouroglou str.
11525 Athens GREECE
Τ. +30 210 6779875
F. +30 210 6779269
e-mail. info@vibro.gr
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So is the goal now, Antonios, to construct a decoupled floor (of wood damped underneath) and floated walls that do NOT sit on the wooden floor?

While I would still have to consider either the existing concrete or a more massive measure, I understand the concessions made in each individual build process. My only concern is that, like the first attempt at this project, the walls set directly on top of the wooden floor, and that is not a benefit to the client.

Thanks for your time and thoughts on this,

Photo Update

FRAMING 01 FRAMING 02 FRAMING 03 The gap from the concrete until the first layer of gypsum-board is 15cm, except one side where is a 25cm. 9cm of low density rockwool and 18cm in the bigger size gap have been placed and 3 plies of gypsum-board have been placed as well.

I'll post some more picture later.

I will be glad to hear any comment-recommendation

ENTRANCE VIEW On the exterior side i will add 4 layers of gypsum-board in total

ENTRANCE VIEW CLOSE-UP WALLS

Hi Antonios, and welcome to the forum!

Thank you for joining in, and explaining your point of view. And please do stick around! Occasionally we do get people from Greece asking questions here.

which unfortunately he could not afford and decided to proceed with a DIY method, which is absolutely respected.

Absolutely! That's what this forum is about, mostly. Even though John is a professional designer, and does studios all around the world, one of the reasons he started this forum is to help out guys like Beeros05, who prefer to go the DIY route. Not everyone can afford to hire professional designers, so this forum exists to help out those guys with good advice, for free.

In Beeros05 case the below structure was suggested based on techno-economical parameters. Despite the limited budget, we try to fit the Room in Room requirements in this construction, more specifically:

While I totally agree with the method you propose for the ceiling (and I think Brien will most likely agree on that too) my doubts are with the wall and floor isolation.

We propose walls to be constructed with multiple layers of gypsumboard + a layer of viscoelastic material

Totally agreed. I guess you mean something like Green Glue for the CLD?

all floating walls

That's where I'm not so much in agreement, as I don't see the need to float the walls: Of course, you went there and inspected the premises, while I didn't, but I'm wondering why you need that. You mention three reasons: "prevent structure-borne noise", "avoid bridges throughout the whole dry wall construction", and "prevent uprising moisture". Moisture, of course, is not an acoustic issue, and we were never informed that there is a moisture problem in that room, so we'll leave that out. Since your first reason was "prevent structure-borne noise", I'm assuming that's the main reason. But where is this noise coming from? It can't be going out, since a massive wall such as we all agree on is not going to transmit much air-borne sound within the room into the floor, so you seem to be implying that there is already noise in the building structure itself which you are trying to prevent from getting into the walls. Is that the main purpose of floating the walls? To prevent noise in the existing structure from getting into the room?

We are aware that mineral wool is often used as a mean of flooring vibration isolation. Being in the field for almost 30 years now, we are unsure of the rebound capabilities of mineral wool and also long term creep behavior, especially when it is loaded by variable loads over the years.

That's why mineral wool was not the original suggestion: I originally suggested OC-703, which works very well in this application. But now it seems that Owens Corning products are not available in Greece, so I guess that's why mineral wool was substituted.

Hence allow me to say that 3Hz is next to impossible, especially when we are talking about rubber mounts (and not springs).

Exactly! Galaxy does use a form of rubber as part of the isolation system, but that's more for high frequencies and as damping, while the springs take care of the low frequencies, and they do indeed get down to 3 Hz like that. With floors that weigh over 200 tons.

I believe beeros05 must have misunderstood or misread the technical specifications provided.

I agree. Reading the specs on your web site, it makes it clear that frequencies "down to" 4 Hz can be attained, but only with multiple layers of your products sandwiched with other materials, and only for heavy, massive loads. At least, that's what I understand from reading your specs, and that makes sense. I think Beeros05 also misunderstood a comment that your made, about not needing any mass on top of the isolation pads: of course, mass IS necessary. Without mass on top of the "spring", there can be no tuning, and thus no isolation.

...can be found on the following link:

Unfortunately, I don't understand Greek, so I can't read the details on there, but it seems to me that the diagrams does indeed show a platform with appreciable mass resting on your pads. The graph and table speak for themselves, and show the performance of the product, but I can't read the information on the diagram that shows how the floor is built.

The final result in Beeros05 project will be highly dependent on the skills and experience of the onsite installer.

Most definitely! The best design in the world is only as good as the guy who builds it. Let's just hope that the builder in this case can follow your instructions exactly, and that it will work as intended.

To be clear, I don't doubt that your design will accomplish what beeros05 is trying to do (provided that the doors/windows/HVAC/electrical part are also done correctly), but to be honest my overall impression is "overkill". In other words, more than is really necessary. That's understandable, I guess, since the previous design that beeros05 was building was totally inadequate for the need, so it's reasonable that he now wants to go further than is really necessary, so that's my big comment here: there seems to be more in your design than is needed to achieve the goal. The ceiling I agree with totally, the walls are questionable, perhaps necessary if there is already structure-borne noise that must be kept out of the room, but I don't see the need for doing the floor that way, when all that is really needed is to keep the drum kit isolated and decoupled from the concrete, which can be accomplished with a simple drum riser. It isn't necessary to do the entire floor. That's my big issue here. It is nice to do the entire floor, sure. But not necessary, and you do run the risk of creating a resonant system that isn't tuned correctly, and doesn't "float", if the builder doesn't do things right.

Anyway, that's just my opinion.

- Stuart -

Silencers are placed outside the room right? I have to put the tubes in a "box" with insulation and the tube must be in a "snake form" right? I dont have much space...

That's sort of the idea, yes, but the tube doesn't need to go in the box. Here are a few examples of how to do HVAC silencers:

http://www.johnlsayers.com/phpBB2/viewt ... r&start=74
http://www.johnlsayers.com/phpBB2/viewt ... 25&start=2
http://www.johnlsayers.com/phpBB2/viewt ... 42&start=5
http://www.johnlsayers.com/phpBB2/viewt ... 61&start=0
http://www.johnlsayers.com/phpBB2/viewt ... cer#p89855
http://www.johnlsayers.com/phpBB2/viewt ... cer#p96578
http://www.johnlsayers.com/phpBB2/viewt ... ok+#p97928
http://www.johnlsayers.com/phpBB2/viewt ... r+#p110641

The key point is to build them from heavy materials (eg: 18mm plywood) and to make sure that the cross-section inside the box is at least twice the cross section of the ducts coming in and going out. For example, if you are using 6 inch ducts, the cross section is about 180 cm2, so you need to make sure that, at all places inside the box, the cross section is at least 360 cm2. The box also needs to be lied with duct liner. Some people just use ordinary fiberglass or mineral wool, but that degrades over time, so proper duct liner is the best option.

As you can see, the silencer does not need to take up much space. You can arrange it vertically, horizontally, diagonally, or any way that will fit. It can be designed so that the duct coming through the wall goes directly in to one side or one end of the box, and the outlet is at the other end.

- Stuart -