Latest tips for my Studio

Discussion in 'Acoustics (Live Room, ISO Booths)' started by jerem1, May 5, 2019.

  1. jerem1

    jerem1 Active Member

    Joined:
    May 5, 2019
    Location:
    Paris
    I note that in that "simple layer mass" ceiling : create a disassociated wood frame / put 10 to 15 cm of wool in the bays / acoustic dry wall 19 mm / heavy mass 5 or 10 mm / acoustic dry wall 13 mm. We have not a mass-spring-mass system but only spring - mass, except if you count the existing room ceiling as the first mass. If you count the ceiling, yes it is exactly a mass-spring-mass system.

    Sorry, i am ashamed to insist, but i really need to be sure.
     
  2. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Location:
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    There is no need for clips and channel when you have an independent wood frame. Clip systems are only for attaching to existing construction.

    The air space between the existing structure and wood frame is the "spring".

    The wood frame holds more mass than the clips could. You'd be reducing your isolation with the clips, and increasing cost significantly.

    You want the standard thickness of "classic" insulation that fits into the wood frame.

    Save the rockwool for the acoustic treatments.

    No problem. Insulation offers very little isolation.

    Most likely you'll have 2x4 wall studs, and a 2x6 or 2x8 ceiling joists. This depends on the ceiling span.

    GG is only for increasing isolation between mass.

    For sealing use a standard Non-Hardening SILICONE, or BUTYL caulking.

    Acrylic will crack over time because it hardens fully.

    A 2x6 ceiling joist, with 3 layers of 5/8 drywall, with GG in between equals 5x layers of drywall, which is good.

    Having no DB level of your drums to go off of its tough to estimate.

    Also since your existing assembly and your new one doesnt have specific test data its not easy to estimate.

    Based on the additional mass and the chart your looking at something around STC 65, with your existing ceiling, decoupled wood frame and 3x layers drywall + GG.

    This is equal to a standard double wall with 2x layers each side.

    Will it be enough? It really depends on whats directly above you. If its a quiet office, then you could have issues. If its a loud kitchen or retail store playing music on a system, you should be ok.

    To give expample.

    One studio i built has the a STC 65 type wall between drum room and control room, with the kit 3 meters away from control room. No sound bleeds between room, dead silence.

    The booth next to the drum room also has an STC 65 wall between them, but the kit is less 1 meter away than the booth. The kit can be heard by ear in the booth, but doesnt get heard by the mics. Part of the reason is the door isnt as thick as the walls, the other is how close the kit is to the room.

    I measured a 45DB reduction in sound with a sound meter, between the booth and drum room, measured 1 meter away. STC ratings are based on 1 kilhertz frequency. So they tell you how many DBs get blocked at 1k. This is how a STC 65 wall can only block 45DB full range, even when buit properly.

    So to give a very, very general estimate Your looking at blocking 45-50db. So if your drums are quiet at 100db, then you block 50db, there's roughly 50db of bleed into the upstairs.

    Make sure you check the test data for this, and that it is worth any additional cost. Often standard drywall is preferred over "quietrock" and other specialty drywalls. Bur if space is tight it might make sense.

    Insulation is whatever fits into the bays. I would consider using only the thickest drywall for each layer. So 19mm only, no 13mm.

    You want the insulation in the frame, and all drywall layers attached to the frame. Just like the drawings in rods book.

    The existing ceiling counts.
     
  3. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Location:
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    Zoom in on the charts below the drawings to observe how your isolation changes depending on the frequency.


    Screenshot_2019-05-22-19-13-11.png
     
  4. jerem1

    jerem1 Active Member

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    May 5, 2019
    Location:
    Paris
    Thank you for all these useful details and opinion.

    I don't understand why because i thought that no matter if you build a wood frame separate of the existing structure or a wood frame fixed to the existing walls like the 2 videos above, it is in my mind absolutely the same need of using channel and clips. But you say that i don't need either channel or clips when the wood frame is separate from the existing wall.

    And by the way so there to i don't need that hat channel that creates space between wool + wood structure and dry wall, a "simple" channel (even if it doesn't create that air space wool + wood structure and dry wall like hat channel) will do the job. So wood frame + wool in it will be very close to each other, no need air in between likes does hat channel.

    So also simple clips can carry the "simple" channel will be ok, i don't need also rubber clips. Just take care a little bit that the clips can carry my layers of "mass" but it is no so important because it is mostly the wood structure that carry it.

    More than than that if i understood you, it may be even possible to have no channel and no clips (clips carry the channel and the screws are going into the channel) , because the mass can be screwed directly to wood structure.

    So what is important here is that first i have no obligation to use hat channel that create that air space, no special clips also, and maybe also i don't need either channel or clips (i need to see with the technician if he can do without clips and channel and screw the mass directly in the wood frame.

    Yes, to be exact there is minimum 1" air between that existing walls and ceiling and the wood structure with the wool in it, all of that, 1" air minimum + the wool is the spring (even if there is of course some wood with the wood frame).

    I called yesterday a technician of the wool company and he was very patient and interesting and he exactly told me what you said. It is a kind of funny coincidence. He clearly told me that for my insulation the mass is the most important and the spring will have very less effect on insulation and absorption because when a wool is placed between well closed dry walls, the wool as a very insignificant effect on insulation and absorption. All the test they did went to this conclusion. And he told me that in contrary when the wool is used inside the room (not in between to well close walls) or in a wall but with micro-perforated boards, that is the case where wool can have impact, effect.

    But for me and it is normal to think about the quantity of spring because more spring there is, more further i am from the rooms or neighbors where i don't want to see my sound going. So in further of that i will see the amount of wool i will put, they have classical layer of 100 mm or 140 mm so for sure it will be one of those. So 140 mm will be better no because of the wool (not very much effect himself into 2 "mass"on insulation or absorption), but because it creates of course more space with 140 mm than 100 mm between me and the others rooms where i try my sound to not (or less as possible) go in.

    I could go for 140 mm to do the most i can for "insulation", isolation, creating more space between and neighbors upstairs, or 100mm so it will give more space for treatment inside the room, and having a bigger room sound as well for recording. It is a difficult choice and i will go to do the maximum to protect neighbors in despite of the quality of the sound inside (because less "room sound" with low level ceiling). There is a little choice here. Maybe it is really more intelligent to do 100 mm because the treatment inside will have an effect as well a little bit in insulation and for the qualities of the room.

    Also putting less wool will give me to add more mass as i talk below. But i still need to respect i think 40 to 60% of wool, so half of the wall or ceiling which is easy to respect eveven with a lot of mass.

    I don't ask an answer because there is so more choices and all are ok but if you have an advice, i will of course take it. Finally i think more to put about 100 mm to have a better room sound, and maybe like that will be goof for more room treatment inside (which maybe could have by the way a also a very little impact on the outside because the sound is better inside).

    i thought that acrylic was more for dry walls because silicon is more for wet rooms. But if you say Silicon is better i trust you.

    I wanted to put heavy mass between 2 dry walls. But because you told me above that the wood structure will be mostly carry the "mass" and i can also do the job without clips and channel, it is really more interesting if i can do like this because without clips that can carry more than a certain weight, if the wood structure carry the weight and if we put a lot of attention on the quality of that wood frame to carry the weight, and also the shrouds (the best shrouds i saw are the RSIC-WHI, or equivalent in France if there is), i can do more than i thought. It is a very important point, i want to do the best for the mass of the ceiling. So with the wood frame appropriate and the shrouds appropriate, i could maybe for the mass of the ceiling, do it will be perfect, 3 dry walls, heavy mass between the 2 dry walls, but for the GG between all of them i don't think i will go for it because even if it "adds dry walls", "mass", it is to expansive (need to put 2 sticks for each dry walls, so for the ceiling and for the 4 walls...).

    Because i really want to put heavy mass every time between 2 dry walls (like in the videos above) because heavy mass is 10kg/m2 (good for mass) if i put GG every time between heavy mass and dry wall boards and for walls and ceiling it gonna be very expansive. dry wall + GG / heavy mass + GG / dry wall + GG / heavy mass + GG / dry wall at the end. So it does a lot of GG...

    But because the ceiling is the most important isolation, insulation i need to care of (neighbors only upstairs) i thing i'm gonna use GG only for the ceiling and exactly as aboce : dry wall + GG / heavy mass + GG / dry wall + GG / heavy mass + GG / dry wall at the end

    In the same idea if i want to reduce and optimize the use of the GG, for the walls, i can use it only for the last layer (the last layer close to my studio) between heavy mass and dry wall.

    So if as you said it can be possible to directly screw at the wood structure (walls or ceiling), but of course with the shrouds appropriate for the ceiling, so it will be possible to add more "mass" than i thought, and less wool as explain above because it as a low effect on isolation, insulation between to well close walls. So i reduce wool to add more mass because it is the most important, effective.

    Thank you for the STC 65 examples, it gave me an impression. As just said above i could also maybe do a little bit better that i thought with dry wall / heavy mass / dry wall / heavy mass + GG / dry wall at the end. So i will put one more layer of mass and dry wall and GG at the end of walls and ceiling (so the layers the most closer to the drum set). I was hesitant for GG but i will follow you. It seems a better product that i thought, and i will try to use at least at the end of the walls and ceiling like above, so a good compromise between not using GG at all, or using GG where it can be the most effective (i would like to use it between all layers, between all boards heavy mass/dry wall, but it gonna to expansive.

    Very good idea also. Because i will have less wool like explain above, i will have more space for "mass". Instead 19mm dry wall and 13 mm, i will use 25 mm the biggest kind) and 19 mm (both acoustic type). And all the time heavy mass in between. If the wood frame (and shrouds/hangers for the ceiling) are chosen in further to carry all that weight, it is really the best i can do. I heard also that is good for frequencies, diffraction, or something like this, i don't remember exactly the term, to use if possible different thickness of dry wall and for sure i will use different thickness.

    So it can be for walls and ceiling, just for the mass part (and with GG at the end between the 2 lats layers) : dry wall 25 cm / heavy mass / dry wall 19 cm / heavy mass / dry wall 19 again. So i close the room with, the last dry wall in the room is a 19 cm.

    Or it is interesting to note that it can maybe do (?) because it could be better the exact opposite, conversely : dry wall 19 cm / heavy mass / dry wall 19 cm / heavy mass / dry wall 25 again. So in that case the bigger dry wall is at the end, in the room.

    Or intermediate : dry wall 19 cm / heavy mass / dry wall 25 cm / heavy mass / dry wall 19 again.

    So there are also the exactly the same options with 2 layers of 25 mm and 1 layers of 19. If i have the space to do it.

    What can be interesting to know here, is if we could be a more effective solution, formula, arrangement : put the thicker layer of dry wall at the beginning of the "mass", in the middle, or at the end, close to the studio, the drums, the sound. Maybe it can do is a difference, maybe not, i have absolutely no idea. I don't ask really the question because all will be ok but it can be interesting to know when there is 2 thickness of dry walls and 3 layers of dry wall.

    Also you said 2"x6" ceiling joist wood can carry 3 layers of dry walls. Maybe we will need to have bigger joists for the "mass" i described above.

    - All the rest is very very clear. So above just some commentary and new ideas, progressions.
     
  5. kmetal

    kmetal Kyle P. Gushue Distinguished Member

    Joined:
    Jul 21, 2009
    Location:
    Boston, Massachusetts
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    The wood frame doesnt touch the existing structure. This gives you mass-air-mass. The air is the "spring".

    No clips necessary with decoupled wood frame.

    Correct!!

    Clips and channel are not necessary. A decoupled wood frame gives the best isolation possible.

    Airspace is the "Spring".

    The insulation is a "dampening" entity. Like tea towels, or moon gels on a drumhead.

    Use the standard thickness insulation for your walls and ceiling joist size.

    Rod told me to use silicone...

    Look into bulk GG and caulking. Buying by the small tube adds up fast. You can get caulking in a large bucket, and GG as well, last time i checked a few years back.

    Make sure you verify GG is even tested use between "heavy mass" layers. Ive only seen testing for its use in drywall, that i can recall.

    I woud use all 25cm for each layer.

    The order of the drywall and mass does not matter. Its functioning as one unit.

    The amount of load (drywall) depends on the span the joist.

    1. figure the span

    2. Check the smallest joist rated for the span

    3. Check that joists load bearing capacity

    4. Compare that with your intended mass.

    5. Remember screws, lighting, wires, caulking, glue, acoustic treatments, and the Joists themselves count as the load / mass

    A structural engineer is reccomend to sign off on the final design. There are plenty of charts online which help architects plan such things.
     
  6. jerem1

    jerem1 Active Member

    Joined:
    May 5, 2019
    Location:
    Paris
    Thank you very much.

    I understand that i have the choice to just leave air in the wood frame. But i prefer adding some wool because i heard that it is always better to put a wool than nothing/air, but maybe not, because if i reed you and what told me the technician of the company ("with the same thickness of "spring" and 2 well close mass at each parts of the walls the type of the wool will be insignificant", after laboratory test). So with the same thickness "spring", if the kind of wool have no impact, we can also maybe conclude by extension that, with same conditions, same thickness of "spring" and 2 well close mass at each part of the walls, between air and when the wall there will be no effect on insulation, isolation, or absorption. But the test they did was between different wools and no between wool and air but maybe it will do the same, and for sure i guess very less effect.

    So i will see what i am gonna do. Nothing in the wood frame or little bit of wool because it reassures me, and furthermore it doesn't take space because it is in the wood frame. I guess there is always a little bit of sound that crosses the first layer of mass, so wool can have a maybe minimum "dampening" insulation, isolation impact and i will take that little chance. Also wool is good for thermal insulation i guess.

    So if as he told me the kind of wool have no effect (no matter level of AFR, Resistance Air Flow) when same thickness and 2 layers of mass are to the extremities of the wall or ceiling, i think it can be interesting to go on rockwool 70kg/m3, not for absorption (no effect as said...) but to add a little bit more "mass", even if it is nothing in term of mass comparatively to the heavy mass (10kg/m2) and dry walls. So that rock wool is still spring comparatively to the "mass" at each parts of the walls (and ceiling), but it just add a little bit of mass. Maybe it is very little more insulation comparatively to air, but i will take that chance.

    Yes, the wool gonna be in the wood frame and in the "bays" of the wood frame ceiling and gonna be around the thickness of the wood frame. For the ceiling for sure in don't want to put the wool on the wood frame but in the wood frame, in the "bays" because if i put it on i am gonna loose some height. So as you said above the 1" separation + the frame himself gonna be the spring and if i put some wool it gonna be only in the wood frame.

    Here is a very detail, no need to answer : i will also see with the technician (even if just air will be ok) how to maintain the wool in the frame (maybe some normal kinds of wires are needed, maybe some thin metal channel) because in that decoupled wood frame there is nothing in the side between the existing wall and the wood frame so i don't want the wool to "fall" into that 1" space (indeed it is not the case of the videos where the wood frame is"glued" to the existing walls, the wool is easily in place because it is stuck to the existing wall). It is a detail and also i can do without any wool, but i will see that because it is just interesting to know how the wool can stand, maintain in place with a decoupled wood frame. For the ceiling i guess we have some thin channels under the wood frame to maintain the wool who is in the frame, and for the walls also and the thin channel (or wires) are in both sides of the wood frame to maintain wool in the frame (and of course in the frame we have some wood boards doing some squares in the wood frame to pose the wood on them + wires or thin metal channel to maintain it). Short, it is just a detail, i will see with him.

    ...

    All the rest is also clear.

    Thank you very much also because i understood (i think) that channel and clips are no used for assembly requirements as i thought, but for adding some air, spring and also make a decoupling between wood frame+wool, and mass. So if i understand in those videos they do a not between the existing wall and the wood frame, but between the wood frame and the mass, thanks to the channel and clips. So i don't understand why they don't just do a decoupled wood frame directly as i do. Maybe they don't know in those 2 videos that it is de the best option to decoupled before and not after as they do with channels and clips.

    So maybe they do like to because they "don't know that the best solution is to make a decoupling before the wood frame and not after (with the channel and clips). So i understood that those channel and clips are no here for needs construction but to create more space, spring and also have a decoupling between wood structure and mass, but it could be better to make that decouplation as you suggest me, between existing wall and wood frame.

    I will see for the large bucket of GG and for the GG with heavy mass (i can send an email to the company) because i also saw that it was between 2 dry walls.

    The 25cm for each layer is a great idea ! I hope we can make a wood frame and found shrouds that can support 3 time 25 cm dry walls + heavy mass in between each layers of dry walls.

    I will see with the technician because it is also a detail in construction, that if the wood frame is enough strong, maybe we don't need shrouds for the ceiling and can screw all the mass directly to the wood frame, but i do not think there is enough long screws to do that, so maybe shrouds with channel will be needed and also because i will reinforce the capacity of the wood frame to carry the mass.

    And yes the wood frame will be very important, we need to be sure that it can support the weight of the "mass". It gonna be an interesting thing to discuss with the technician.

    The technician is an electrician so we saw all of this : no light into the room, just some electrical outlets, kind of boxes that are not in the walls but outside to minimize holes, and light that buy i connect to those electrical outlets.

    For the door i think we will do a sas, 2 doors system.

    Thank you again.
     
  7. jerem1

    jerem1 Active Member

    Joined:
    May 5, 2019
    Location:
    Paris
    Just a little edit only for that paragraph to make it more clear :

    Thank you very much also because i understood (i think) that channel and clips are no used for assembly requirements as i thought, but for adding some air, spring, and also make a decoupling between wood frame+wool, and mass that closing the wall. So if i understand in those videos i have put they do a decoupling not between the existing wall and the wood frame, but after, so between the wood frame and the mass that closing the wall, thanks to the channel and clips.

    So i don't understand why they don't just do a decoupled wood frame directly as i do. Maybe they don't know that it is the best option to decoupled between the existing wall and the wood frame and not after as they do, between the wood frame and mass that closing the wall (with channels and clips).

    So if i understood those channel and clips are no here for needs construction but to create more space/spring and also and maybe mostly to create a decoupling between wood structure and mass. But it could be better to make that decoupling as you suggest me before, between the wall and wood frame and not between the wood frame and the mass as they do.
     
  8. kmetal

    kmetal Kyle P. Gushue Distinguished Member

    Joined:
    Jul 21, 2009
    Location:
    Boston, Massachusetts
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    I cant speculate as to why people make incorrect decisions. There is a vast amount of mis-information out there in acoustics.

    The things i do come from Rods book. Rod is a world class studio builder. His methods are backed by test data. I've read several of his reference materials as well as his books. When i use those methods, they work. When i have not used those methods, i have been very disappointed. I learned after my first build to trust the tried and true methods, and have not been let down since.

    In my mind rod and others did the hard work of defining a proper method. Its up to us to follow it.
     
  9. jerem1

    jerem1 Active Member

    Joined:
    May 5, 2019
    Location:
    Paris
    Kyle, I thank you again.

    Things could have been different if i had not gone over this forum.

    Best regards and thank you infinitely.

    Jeremy
     
  10. kmetal

    kmetal Kyle P. Gushue Distinguished Member

    Joined:
    Jul 21, 2009
    Location:
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    Best of luck, dont forget to check back in with your progress!
     
  11. jerem1

    jerem1 Active Member

    Joined:
    May 5, 2019
    Location:
    Paris
    Hi Kyle,

    Yes of course ! I thank you again. I have read once again all the posts from the beginning and everything is absolutely, absolutely clear. I asked a lot of questions more than 1 time because i wanted to be sure to understand, and you took the time and energy to answer until i understand. So thank you again.

    Best regards.
     
    kmetal likes this.
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