Green Glue / needed?

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There is an announcement at the top of the forum about what to do to assure getting as many responses as possible. The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes. - Stuart -

hi Stuart and everybody else! my intention wasn't to ignore justified rules - it was just a matter of time. yes, i overlooked to include the location, and for the rest i thought i gave a reasonable bit of detail. let me say few more words: it is my private studio to be, mainly for my own creative work but not excluding other people projects, also those of commercial nature. above the wine cellar is an apartment, so thats one thing to consider. the walls in the live area are to be left as they are, just a stone cleaning/polishing, but no any layers on them except some acoustic panels that will materialize when possible. control room is an hexagon with angles of 97degx2 and 131.5degx4. at the moment, the floor (bottom) is elevated cca. 90cm down and all structural foundations are reinforced, with 5 pillars built. concrete floor is done. before continuing with the floor isolation and floating, i need to elevate the ceiling down and thats where i came with question about green glue (or nothing?). my layers are listed in a previous post. once again, sorry for not fullfiling all the details form the start. cheers, d2k

For your ceiling, I would forget about the particle board and the 12.5 mm gypsum board. I would just use two layers of 16mm gypsum board. The 12.5mm gypsum board you mentioned is too thin to be good for isolation. Use only 16 mm (or if you can't get 16mm, then 15 mm is fine). The same goes for your control room ceiling: you probably don't need so much up there. Here again it would probably be fine with two layers of 16mm gypsum board. If you can't afford Green Glue, then don't try to substitute something else! There is nothing else that has the same properties, that has been tested and shown to work like GG.

before continuing with the floor isolation and floating,

Do not try to float your floor! That would be a bad idea. You already have a concrete floor, which is excellent. You don't need anything else. If you don't like the look of concrete, then put something like laminate floor on it, but don't try to float it: Regarding floating floors: viewtopic.php?f=2&t=8173

control room is an hexagon with angles of 97degx2 and 131.5degx4.

You are wasting a lot of space like that! And you are eliminating the areas where you need to put bass traps and speaker soffits. And you DO need to fill in your location if you want continued help on this forum. - Stuart -

Soundman2020 wrote:

For your ceiling, I would forget about the particle board and the 12.5 mm gypsum board. I would just use two layers of 16mm gypsum board. The 12.5mm gypsum board you mentioned is too thin to be good for isolation. Use only 16 mm (or if you can't get 16mm, then 15 mm is fine).

hi Stuart, thank u for the comments. i was strictly adviced to put particle board. I also checked today, and it should be possible to get 15mm gypsum boards. Can you please tell me a bit more on why particle board is not good idea, and if 2x15mm gypsum would provide better isolation on its own (ofcourse + stone wool)?

If you can't afford Green Glue, then don't try to substitute something else! There is nothing else that has the same properties, that has been tested and shown to work like GG.

thx! thats why i asked. many people are trying to convince that there are some other "equal in effect" glues/liquids/whatever, but i was always sceptical... one of those is from http://www.soudal.com [fixx all, fix all crystal and soudal panel system]... as u suggest, i am better off not using anything when i can not afford GG, i was just not sure if it is ok to leave layers like they are while, ofcourse, tapp and "close" all joints and screwholes.

Do not try to float your floor! That would be a bad idea. You already have a concrete floor, which is excellent. You don't need anything else. If you don't like the look of concrete, then put something like laminate floor on it, but don't try to float it: Regarding floating floors: viewtopic.php?f=2&t=8173

as i am not going to treat my main original stone walls with anything (they are to be left as thay are for dispersion, etc...) i am affraid that vibrations from drum playing are possibly going to make impact on a concrete structure. so i thought of putting hydroisolation next on a concrete (i need this!) then stone wool of 160kg/m3, then estrih and finally real oak parquet. estrih and parquet would "swim" in wool. both in control room and studio... in any case i prefere to have parquet. i am going to read more on the net and on suggested link about why this would be bad idea when my logic is telling me i should do it... but again, i respect your opinion...

control room is an hexagon with angles of 97degx2 and 131.5degx4.

You are wasting a lot of space like that! And you are eliminating the areas where you need to put bass traps and speaker soffits.

again, i was adviced to do so... as it was said, this way i eliminate reflections problem from a start and then later tune the room to desired effect. i visited some rooms of this shape and was blasted by a sound image. and, my base concrete is already shaped for the hexagon and elevation and difference in hight is already done. but, as always, i would like to hear more from u if u care to explain it to me a bit more. also, i like to hear what would you do with a space that is left on a top left corner on a top plan? right next to that wall is a road and i am ot sure wheter to fill that "triangle" with something. thank u for the comments and help, i hope that i dont bother u way too much ;-) d2k

Can you please tell me a bit more on why particle board is not good idea,

well, you CAN use it if you want to, but you don't NEED to use it. It won't be as effective as gypsum board for isolation, and will cost more. In order to isolate, you need mass. Gypsum board is much more dense than particle board, and cheaper (in most parts of the world). So comparing kilogram for kilogram, thick gypsum board is the best and cheapest way to do it. Two layers of 15mm gypsum board is about the same total mass as what you had in your original plan, but since it is more dense, it uses up less space (total thickness), and costs less. The person who told you to put the particle board on the ceiling: Did he say WHY he thinks you need it? Perhaps it was for structural reasons, not for acoustic isolation reasons?

many people are trying to convince that there are some other "equal in effect" glues/liquids/whatever, but i was always sceptical...

Yeah, there seem to be a lot of people that just do not understand what Green Glue actually is, and they think you can substitute other things instead! But there really is nothing else like it. It is NOT glue at all: it is a very specialized acoustic damping material, so you cannot use any kind of glue to replace it.

i was just not sure if it is ok to leave layers like they are while, ofcourse, tapp and "close" all joints and screwholes.

Sealing everything is VERY important. Seal each layer, each joint, very carefully. Even a small gap can damage your isolation.

i am affraid that vibrations from drum playing are possibly going to make impact on a concrete structure.

A good way of dealing with impact noise form drum kits, is to build a "drum riser", which is basically just an isolated platform for the drums. Much easier and much cheaper than trying to build a proper floating floor.

i thought of putting hydroisolation next on a concrete (i need this!) then stone wool of 160kg/m3, then estrih and finally real oak parquet.

What is "estrih"?

my logic is telling me i should do it

Unfortunately, there are many things about acoustics that are not "logical"! Sound just does not behave the way most people think it does. It isn't logical at all, until you start understanding the basics of how it all works. Most people don't even realize that, from the point of view of a sound wave, even air is pretty hard and stiff, and also bouncy.... :)

as it was said, this way i eliminate reflections problem from a start and then later tune the room to desired effect.

You cannot eliminate reflections by adding extra solid walls: All that you do like that is to change the angle of the reflections. They are still there, but they just go in a different direction. There are several types of reflections that you need to know about, but probably you were told to angle your walls to eliminate flutter echo, which is one type of reflection. Don't worry too much about that: There are other ways of dealing with flutter echo. But there is only ONE way of dealing with the modal problems that all small rooms have: The ONLY way of dealing with those, is with bass traps. Bass traps have to be very large, and the best place you can put them is in the corners. If you cut off the corners of your room, then you have no place to put your bass traps, and your room will sound bad: The bass will not be smooth and tight. It will sound dull, muddy, honky, cavey, and unpleasant. Bass traps are very important in small rooms, so use that corner space for your traps, not for trying to chase reflections. That's not the best way to do it.

my base concrete is already shaped for the hexagon and elevation and difference in hight is already done.

Why did you shape the "base concrete", and why do you have "differences in height"? That is not necessary at all!!!! That is not the way to build a studio in a basement! If you have poured extra concrete on top of the existing concrete floor, then you have wasted money and also wasted room height. For good acoustics you need as much height in the room as possible: if you raise the floor at all, then you have reduced the height. You need as much height as you can get! This might sound harsh, but whoever told you that you need to shape your foundations on top of an existing concrete floor, and that you have to cut the corners of the room to deal with "reflections", does not understand acoustics or studio design. Sorry, but they just don't have a clue.

i like to hear what would you do with a space that is left on a top left corner on a top plan? right next to that wall is a road and i am ot sure wheter to fill that "triangle" with something.

I think you need to slow down, stop all your construction, and plan your studio better before you do anything else! If you have a busy road next to your studio, then "putting something in the triangle" is not going to help at all! You need proper isolation around your room, and you do not have that on your plan. Looking at your plan, I can see several MAJOR issues. They can probably be fixed, but not if you carry on building the way you were planning to. It might be possible to use what you already have built, but we will need to see photos of what you have done already, and much more information on what you are trying to do. For example, in order to decide how much isolation you need, we need to know how loud you are inside that room, and how quite you need that to be outside. We also need to know how loud the noise from that road is, and what kind of noise it is. Plus we need to know what kind of work you will be doing in that studio: will you be recording live instruments at midnight? Or just mixing during the day only? Or just mastering? Etc. Please take some photos of what you have right now, and post them here so we can see where you are and what can be done to fix the problems caused by the bad advice you have been given.

and then later tune the room to desired effect.

There are some things you cannot fix after the room is already built: You need to START by choosing good dimensions, based on one of the known good ratios (Sepmeyer, Louden, Boner, etc.). Then you need to isolate your room properly, but you do not show any isolation on your plans. Then you need to plan the basic layout of your room, showing the correct geometry for the speakers and mix position. Then you need to plan the basic treatment, which starts with major bass trapping in the corners, absorption on all first reflection points, designing a reflection free zone around the mic position, etc. Then you need to consider where you will have your electrical system, and your HVAC system. And once you have all that in place, you need to figure out doors and windows, and how you are going to keep all of those structures isolated and decoupled. You don't have any of that on your plans, and from what you are saying, then things that you have done already are no use at all for what you need to do. So please, stop building and start planning. You cannot build a successful studio if it is not planned correctly. You need to think of everything in advance, and only start building once the entire design works together. Post the photos here, and we'll see what can be done to fix the problems, and design your room correctly. And you DO need to fill in your location if you want continued help on this forum. - Stuart -

hi Stuart, thax again for posting...

What is "estrih"?

sorry, i should write "estrich", it is a 5-8 cm concrete, beton, with a mesh of wires that is used as a surface for laying parquet on it...

You cannot eliminate reflections by adding extra solid walls: All that you do like that is to change the angle of the reflections. They are still there, but they just go in a different direction.

the red shaped hexagon is not only solid walls. Solid wall is just on a right 4 sides and then there is a 5cm of air and shell made of rockwool and gypsumboard.

There are several types of reflections that you need to know about, but probably you were told to angle your walls to eliminate flutter echo, which is one type of reflection. Don't worry too much about that: There are other ways of dealing with flutter echo. But there is only ONE way of dealing with the modal problems that all small rooms have: The ONLY way of dealing with those, is with bass traps.

yes, i am aware of that. i chosen this position partly because of the position of the main doors in a cellar as this way CR is a bit bigger and partly because of flutter. I ofcourse still plan to get bass traps and install them in a corners as well as all other elements needed for absortion and dispersion.

Why did you shape the "base concrete", and why do you have "differences in height"? That is not necessary at all!!!! That is not the way to build a studio in a basement! If you have poured extra concrete on top of the existing concrete floor, then you have wasted money and also wasted room height. For good acoustics you need as much height in the room as possible: if you raise the floor at all, then you have reduced the height. You need as much height as you can get!

no... it is exactly the other way around. as starting hight in a cellar was 2.7m and i know i need a hight, i showel the bottom of the cellar for more than 90cm, making new foundation for the existing support elements. as i do not need more than 2.55m in a CR, that part of the cellar wasn't made so deep because it was cheaper and better for the construction, while live area has more depth, making the clean, treated floor to ceiling 3.00m

If you have a busy road next to your studio, then "putting something in the triangle" is not going to help at all! You need proper isolation around your room, and you do not have that on your plan.

as i want to leave original stone walls, in the live area, there is nothng that can help that much in a term of isolation. road is not that busy (it is a crossing in a suburb of a smaller town, with two regular 2way drives) in a terms that is not going to be possible to record, but i am aware and ready to some compromises. the "triangle" i am talking about is there and i hope it can help with acoustics if i fill that space with something and i am wondering if you can advice on what to fill in that space? to answer to some other of your questions: i do not need to be very quite on any side, except in the respect to upper floors 8) i want to be able to play very loud inside the CR, which is going to be possible with my planned layers. i will respect your advice about omitting particle and increasing gypsum. i am aware it woudl not be possible to record drums in the midnight, only because of the upper floor, thats the compromise i need to live with and it is fine. i will be recording upright piano, drums, guitars, etc... with many other electronic staff like synths and drummachines...

Then you need to isolate your room properly, but you do not show any isolation on your plans.

the red thing represents isolation around CR. there is NO isolation in a live room area. stone walls would remain as they are, while various acoustic elemtns will be hang on those walls and false ceiling for the acoustics. various acoustic elements will be used also in CR. this is situation as is in this moment. cheers&thx, d2k

hi everyone, any further suggestions to my posts above? i understand Stuart could be busy or something... thx! d.

i would probably turn the CR on its side facing into the live room and use the side space for a isolation booth/airlock.

hi Glenn, thx for your input... interesting point, but i like the idea of having large original door width for the purpose of the light into the live room... also, i would consider the airlock coridor as a wasted space as i prefere to have larger live room where also some projections will be going on as well as lecures and workshops. As Stuart suggested, i may as well made rectangular CR with builted bass traps by the book. At the moment is concived as on the drawing with the use of prefabricated various acoustical elemnts like bass traps, absobers, difusers...all over the CR and by the need in live room... something like JOCAVI offers... any other comments? thx, d2k