CONSTRUCTION DETAILS. PLEASE HELP

hi, I'm new in this forum.... we are building a semi pro studio and after reading trough some books, this forum and some drafts that John gave us.. we are coming closer to building one.. here some info What the studio will be used for: Contemporary music, mostly modern< rock stuff but also other styles. Enviroment: On the outskirts of a small village. No big noises. Maybe the cars on the local road.. i hear them in my house when everything is quiet. :) here is a project plan.. more of detail in the basic constructions.. we went with the GUruland control room.. it kind looked best. John suggested the same thing in his draft.. one smaller room will be totaly dead.. and the bigger room will be more neutral to live.. because i have a band (rock ska) with 6 people - drums, brass section, guitar, bass etc. and we will use the bigger room for practice as well.. here is now the plan and then some concrete questions: measuring is metric and in cm the walls: i thought it would be good to use the double wall as on the detail, but i don't know what i should put on the outer side that is looking to the neutral big room, should i put slot resonators.. or something else.. there is so many options and i don't know which fits best for me.. and should i just put another gypsum board on the other side.. puting the carrying 20x20 cm studs (like on the wall detail) in the middle of the wall won't lower the STC? is it ok if i us a lower STC wall (the thiner ones on the sides where i don't need so much STC (between coffe room and live room), and how should i treat the inner part of the room.. ..i read in philip newells book on recording studio design... that i should splay or get as much as non parallel walls as i can.. so we made the ceeling go nonparalel with the floor as well.. as shown in the drawing.. is that ok?.. how should i treat the ceeling? again so many options.. i don't know which one to use. ..should i isolate the outer walls and block the windows i have.. and with what option.. the nosie form outside and inside is not that much of a problem.. but i am worried about the inner acoustics if i leave all the windows.. is it better just to close them all.. and put a low STC isolation.. how should i treat the inner part of the isolation wall (the one that looks to the room) Floors: i will rise the back of the CR and i thought of rising the tottaly dead room (putting .. and because i have tarmat on the floor (long story) i would raise the live room floor a little bit.. now in the book i read.. newell says that if you don't isolate the floor and ceeling, sound will be transmited structuraly and it will end up again in the CR ofcourse more with low freq.. (plus there is an apartment above the stuido.. there is no need for great isolation.. but some would be ok. would be puting a cork floor and then a wooden floor boarding on top enoguh..to get my tarmat a little bit more even and to have the live sounding wooden floor without creeks and nosies when walking? or is it better to do the rockwool, stud, wood boards option? is it more usefull to cut on the bar part (our guitar player is an architect studient and he pushed that ide while drawing) and make the live room biger?? ok... if you see any errors in the drawing that could be improved.. i would be very thankfull.. and suggestions and other stuff.. does anybody now how exactley did the do the back difusors in the guruland CR? and what is behind the walls? here at the end a picture of the space of the future studio (before we emptied it out :) ) Petar

here once more the pictures but uploaded.. and not just links.. because the links don't work Petar

Petar, if your autocad guy has a zip manager you can upload directly to the forum - please save as DXF, then zip these files and upload to the forum as zip files. If you have no way of doing that, please let me know here and I'll try something else. I would NOT recommend using "inside out" walls between the CR and the live room, as you won't get as good isolation by quite a bit - this method cuts down available air gap between your two masses, which drastically reduces low frequency isolation. As to other "guesses" about acoustic needs, you can get a REALLY rough idea of your room's approximate acoustics by using the reverb calculator here - http://www.saecollege.de/reference_mate ... m#verbcalc The basic goal, for a live room, is to get the RT pretty close to the same value (probably around .3 to .4 seconds in your live room) at ALL frequencies - note the little "button boxes" at the bottom of the calculator, for each frequency - you need to check your wall/ceiling/floor settings at ALL these frequencies, and compare to each other. AFTER the rooms are built, you can actually listen and test to see what more needs to be done - The ETF program (about $150 USD), along with a Behringer ECM-8000 mic for about $50 USD is one of the more complete and reasonably priced ways to do this - your ears, along with some WELL-recorded CD's, is another. BTW, I help people from third-world countries in the same order as I do any others; I only have so much time I can donate, and I normally expect COMMERCIAL enterprises to pay for my time especially if they want preferential treatment - otherwise, I take the oldest requests first as I have time... Steve

hi, thank you very much.. i can upload the autcad file.. now it is in a .dwg format i think but i can transfer it to the one that is suitable for you. i will upload them tomorrow :-) thank you for explaining what NOT to do :).. but i would like to get a suggestion what to DO.. :) maybe you can open the autocad drawing and just add the ideas you have and then decribe it just short :) i don't want to take much time from you because i know you are very busy :) so it would be cool if you just say do this and this.., float the floor and how or don't, put this on celeing or don't, on the walls, use this :) you don't have to explain much.. goes faster.. i can find the explaination in the books.. i will post some more pics so you can get a visual on the existing walls and if i should do a minor or biger treatment.. the truth is.. i would need at least some of isolation to the outside.. but i don't know what kind i should use.. if it is better to seal the windows or just leave them and put something on the walls. or maybe i should double them :-) ..and the third world countrie thing was just making fun of myself.. :) i didn't mean to offend you or anything.. :) it was a small joke.. that obviusly wasn't in place :) we ususaly make fun of oursleves in that way.. everybody (here) is striving to be like EU or USA but the fact is we are still so far behind that it is just funny :)

hi, and one more thing.. i put the measures in the calculator and results on all frequencies are about 0 to -0.02 is something wrong with the calculator?

Hi again; sorry I missed the :=) in your "third world" comment - I never know which way to take things til I've talked to people a while - some you think are serious, are not - others you think are joking get really upset when you take it that way - I am normally a complete "smart-ass" and it tends to get me in trouble, so I try to keep it down (usually) - anyway, no big deal now that we're clear (one "smart ass" to another... :=) I'll wait for your cad files, don't have a way to look at newer autocad drawings unless they're exported to DXF. calculator - did you enter values in feet or what? There's a button at the top to change from feet to meters - other than that, not sure. I'm glad you've read some good books on the subject, makes it easier to discuss that way - Need to know a rough budget and some material costs (unless this is not a problem) or at least the type materials that are available to you (gypsum wallboard, MDF, concrete block, brick, wood or steel framing, thick glass, etc - If this is to be a pro facility, I will assume you want EXCELLENT isolation between the CR and live room at least - how loud is the surrounding area (minus gunshots/artillery fire, of course :=)) and would you like to keep the natural light from at least some of the windows? Anything else you may want to know - The simplest decent wall construction is a double frame, with two layers of 15mm gypsum on the outside surface of each frame, leaving a distance from inner surface of wallboard on each side of 200-300mm - this gap filled with mineral wool or rigid fiberglass insulation. Glass for windows should be minimum 9 and 12mm, 12 and 15mm would be better. On the 15mm side, an extra layer of 12mm gypsum between the two layers of 15mm will balance out the isolation so that it's at least as good for the glass as it is for the gypsum. have a look at the last wall on the right, bottom of the page here - http://www.domesticsoundproofing.co.uk/tloss.htm For infinite variations including actual TL at all frequencies measured, download this pdf - http://irc.nrc-cnrc.gc.ca/irc/fulltext/ir761/ir761.pdf Again, for a pro installation I would float ALL floors - both for isolation between rooms and to the outside, and so that there are no differences in floor height between rooms - you want two leaves of mass (with no air gaps between layers of that leaf) between any two locations you need isolation - so your outer shell should NOT have an air gap and two mass leaves, but instead one outer mass with each room providing the OTHER mass of a mass-air-mass system (air usually means insulation, NOT the closed cell foam kind) Ceiling construction - same thing. if your building has a pitched roof, it will probably have an attic that is vented to the outside - keep these vents open, if anything vent it MORE - then, your ceiling should be thickened (make sure it can be supported) and will become your outer leaf - each room's individual inner ceiling can be supported on its walls, which should be resting on their individual floated floor. This gives complete floated room-in-room construction for all rooms. Air lock doors between vox booths, etc, may violate the "2-leaf" rule in order to keep isolation while doors are opened during recording - this can't be helped, but WILL worsen isolation somewhat. Because of this, any walls affected should be increased in mass from the 2-layer, 2-leaf design. Let me know what else you need to know, waiting for the DXF's... Steve

hi, i am back with the updates.. I checked out the prices.. and the bottom right wall would cost me about 27 $ per sq. meter (i calculated the double isolation wood, gypsum boards..) gypsum 16mm sq meter - 3,50 $ isolation 10 cm thick - 3,20 $ (there is a special acoustic isolation but 8cm for 4,10 $ but in the STC graph it has the same values) STC 125 - 20 db 250 - 40 db 500-4000 hz - around 90db wood 5x10x100 cm for one square meter about 1 $ (i estimated screws and everything else in the total value) i have a budget of 8000 $ for materials and if i need to i will maybe be able to push it to 9000$ i have glass about 1,5 to 3 cm thick for free different dimensions (i will make a list but that is not important now.) i estimated that this thick wall is about 66 sq meters in total so it would cost me roughly 1700 $. We estimated that the basic wooden construction (without the walls construction) will cost us about 500 $ (the 15x15 cm wooden pillars that will carry the whole ceeling and stuff.. explained in the DXF) so 1600 $ for the heavy walls 400 $ for the thiner walls (in the dxf) 500 $ for the basic wooden construction) that leaves around 6000 for other things :-) i understand the walls now.. but the ceeling and floor is not yet clear.. ..and i didn't think of floating the whole area.. i thought just the live room, the vocal booth, the back of the CR.. the lounge and the CR would have a wood or heavy carpet flooring the noise outside is low.. usualy very quiet, just wenn a car passes by, i don't know how much i should estimate.. but lets put around 55db ? :) i know that 35db is the lower hearing limit. but when we play with the band (rock band) you can hear it pretty loud in the apartment upstairs and the otside.. but that is not a big problem.. if we could lower it just a little to the outside and some more to the roof would be great.. since the apartment upstairs is mine and only my wife will kill me if the baby awakes at night :) (we are not yet married but i am planing in long term :) ) i added a few pictures of the hall we are planing to build it in.. from the outside and the inside (the hall was full with cars and books and garbage at the time of taking pictures, but now it is almost empty :) i think it is always best to have a visual on it :) the floor is made of concrete and a tarmat layer on top (asphalt that is used od roads) .. i couldnt find any isolation data on tarmat. but since it has tar in it, it should be at least some sort if isolation or? hope u can use the DXF files :) i saved it in 3 possible Save As options.. hope one works.. :) and just want to thank you again for helping me so much! :) you are great!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Petar

i faound the isolation for framing.. it is calles ARMAFLEX AC www.armaflex.com and you can get it here in croatia. here the discription Armaflex AC flexible, closed cell, elastomeric nitrile rubber insulation Material Foamed nitrile rubber 13mm thick is 16$/sq meter, 19mm is 24$/sq meter the same company has something called armafoam sount 240, but i can't get it here in croatia.. is it enough to use 13mm thick?.. and if i use an adhesive (the same company has it) to glue it to the floor and the frame.. do i need the acoustic sealant still? thanks.. :)

..and i forgot to ask.. is stell studs better than wood? just say Yes or No :) because i can choose.. ..but we went for 5cmx8cm for now (wood, timber)..

I'm not finding enough info in english about the armaflex stuff - do you have specs such as durometer on it? For framing, I prefer wood but it's mostly because I'm an OLD fart that's used to it I think... Acoustic sealant - this has nothing to do with supporting a floor on some type of rubber - you want acoustic sealant ANYWHERE there would be an air leak in your oonstruction. If you've not already done so, read through the "sticky" section, specifically the first half-dozen links in the REFERENCE section. Still haven't had time to look at your drawings, hope to in the next couple days; it's been pretty hectic around here lately... Steve

hi, i am sorry.. there is no info about it.. the closest i could get is the pdf file i uploaded now.. but maybe i could test it the way you described in one of the sticky topics.. it should be only 20% squeezed.. because on both ends 100% and 0% it is not good i had it in my hands.. it is soft when you sgueeze it.. but it feels really strong between rubber and a sponge.. :) ..and about the drawings.. :).. wait.. i will give you more detailed drawings tomorrow.. we have all the info about the floors as well.. Petar

hi, i am back with updates.. we started with building a few days ago.. first we are building the heavy framing that will carry the ceeling.. and it is supposed to look like this.. (3ddesign.jpg) ..after we frame that part.. we will frame the walls.. ..i am putting all wooden posts on 3 cm rubber 0,5cm /neoprene 2cm / ruber 0,5cm plates ..i hope that reduces noise transmission.. it is hard to explain how i did it.. i will post some pics on monday.. easiest to explain by showing the pics.. here are some pics of the wood and the crew building :) my brother (worker/helper), my grandpa (worked as carpenter in the 1950's but later became a medical doctor... he does it all oldschool.. ..he knows what he is doing.. i will show you the pics), me (helping with all the metal stuff and) and my granpas friend (holding stuff for granpa :) hehe) ..we worked 2 days.. and have half of the stuff cut out.. (i will post those pics)... ..the working atmosphere is great and we have alot of loughs :)

Petar, looks like you're on the move - I'm glad you've decided on wood framing rather than steel; I just came across some info the other day regarding moisture in buildings, and wood framed(and wood sheathed) buildings can absorb 10 TIMES as much moisture as steel framed /gypsum sheathed buildings; masonry construction can absorb 10 times as much as wood before problems are encountered. So, if your climate is very humid then either wood or masonry seems to be much better for moisture control. I've added more info links on moisture control, etc, in the REFERENCE section if you're interested. The rubber you describe sounds like it may be a bit "squishy" for your needs - also, I have NO IDEA what it's lifetime will be without more data, so I'm gonna say that I don't think you should use that. If you mess up a floated floor, you can make things WORSE than without it... Steve

hi, here the ruber thing. i bought this heavy rubber in a tyre company.. they said it is long lasting.. at least 30 years.. and i bought 20mm of heavy elastomeric (neoprene) material.. i got it in sheets so i had to cut it out... it was prety expensive.. about 150$ for 2 sq meters of rubber and elastomericsheet togeather.. i tried to go over the neoprene stuff with my car and it went down only 40% so it is pretty robust when we put the posts up it didn't squeeze a bit.. but i think when we put all the stuff that goes in the posts and and the ceeling.. that it will come to 20% like you described in some other thread there is a "spongier" neoprene wihich i will use for the floating floor and the walls because it has more surface then the posts.. this one i can get 20mm thick 10 sq meter for 180$ ...but i will buy that later.. on the other picture is shown how we did

here is picture how we anchored the posts in to the ground.. made a 12mm hole in the wood.. then put a metal bolt.. (like on the picture) in the wood, put the sandwich (ruubber, elastomer, rubber) and a rubber hose 5 cm long on the metal bolt all togeather it went into the ground (in the hole we made 10 cm deep) so wenn all settels. the metal bolt cant touch the ground.. it only prevents the post from going left right.. :) and so the wooden post is in no direct contact with the ground :)

on the sides where the wooden posts could touch the existing wall.. i put rubber (also bought in the tire company) 25 mm so there is no chance the wood comes in direct contact with the existing structure.. i did it like on the pictures.. this heavy rubber is on all sides of the post that look to to an existing wall (on all posts in the room)

..it is the end of the day.. we put three posts up!!! :) tomorrw it will be the first half of the construction. here a few pics how it is starting to grow :) and a pic of my CREW: My brother.. my granpa and his nephew :) hehe... my granpa learned the wood art after the second world war.. with the german guys who where freed from captivity.. :).. (he said that they where good carpenters... )

hey, here are new pics.. we finished some part of the live room.. it is looking good.. how do you like it.. one of the pics it show how high the lower part of the splayed ceeling is (my two brothers standing underneeth) and on the other shows how the joists will be.. (span of 5,8 meters ..and 60 cm between each josit) they are good quality and 16x8 cm so no worry that it will crash down.. ...now for the ceeling.. and the isolation to the outside (existing walls)walls.. for the LIVE ROOM Ceeling: i thought i would put on top of the joists one layer of gypsum boards, between the joists 10 cm of glass or rockwool and under the joists i would just nail a cloth (special heavy cloth).. so the rockwool would both work for isolation and room acoustic treatment.. because the wool is 10 cm and the joists 16 cm.. my question is.. should i glue the wool to the gypsum boards of should it be gypsum, then 6 cm of air and then the wool.. ? what do you think about that idea??? do you think that would be good acoustic treatment? outside walls.. should i just stuff it up with wool and cover it with a cloth or a slat resonator.?? or should i put one layer of gypsum boards as well??.. i want the wall to be acoustic treatment as well as some small isolation.. as you can see on the pic with my two brothers, there are 3 windows on that wall.. and my question is: should i leave one or two open (i would do a double window thing) build one aditional window in the inside.. (same principle as double doors :)) i don't know how windows will have an effect on the acoustic treatment of the room.. windows will be paralel to the glass between the CR and the live room (the glass will be exactley where my two brothers are standing) please some help and advice.. anyone is welcome.. DRAWINGS would be great.. i am a visual kind of guy.. that is why i put so much pictures on the thread.. so you can visualise as well :) hope to hear from somebody soon p.s. one more thing.. when you frame the walls.. and put neoprene under the framing.. how do you fasten the frames on the floor and on the ceeling??? should i do it similar how i did it with the pillars? i will first do the walls down to the existing floor.. and then i will maybe float the floor inside.. so all the walls will stand on the existing floor.. :)

Sorry for the delay, been really busy - "because the wool is 10 cm and the joists 16 cm.. my question is.. should i glue the wool to the gypsum boards of should it be gypsum, then 6 cm of air and then the wool.. ?" - I would put the wool even with the bottom edge of the joists, this will let it work to lower frequencies by giving it an effective depth of 16 cm instead of 10 - but don't expect any isolation from the wool, that only happens if there is wallboard on BOTH sides of the wool (like INSIDE a wall or ceiling) Outside walls - "should i just stuff it up with wool and cover it with a cloth or a slat resonator.?? or should i put one layer of gypsum boards as well??.. i want the wall to be acoustic treatment as well as some small isolation.. " If that's what you want, you need to find a way to do one of John's "inside out" walls - since you're not looking for MAXIMUM isolation, this shouldn't be a problem. What MIGHT be a problem is building the wall on the floor, putting the wallboard on one side, and THEN tipping the wall up into place - these can get heavy, and you might need more help to do it that way. windows - natural light and a view are usually good things, and since you don't need a LOT of isolation, again I would try to keep a window or two. This would mean good seals on the existing ones, probably an air gap between old window and new (part of the new wall) - 250 to 300mm is a good air gap for sound windows, and the glass should be about 1/3 as thick as your wallboard total. This will keep the glass from being much of a weak spot. I would NOT put rubber under your wall frames - it's too easy to end up with a bad resonance in the wall, ESPECIALLY since we don't have ANY specifications on the rubber you're using. You would be much better off just framing those walls normally, and making some sway braces for the tops of the frames - if you will have an inner, false ceiling resting on the tops of the walls, then you may not even need sway braces at all. A better way would be to put your rubber closer together around the perimeter of the floated floor, and build your inner walls on top of the floated floor. I hope that helps... Steve

hi, i solved my armaflex (neoprene under the studs) thing.. i searched trough the forum.. anf found a guy who used it.. (his nick is Jazmann) here is what he wrote on this: I used 1/2" but I would recommend 3/4" thick Armaflex closed cell foam under the studs if you are going to build a wall using wooden studs and sheetrock. But if you are committed to using studs and drywall, then OK. Use 3/4" (19 mm) Armaflex under each bottom plate. (You are talking about double-wall construction, of course, right?) Using the foam under the wall has one risk and one big advantage. The risk is that the foam will deteriorate (fall apart) over time and 30 years from now be less effective. In my case, I don't care so much, because I don't I'll hear well that long anyway. ; - ) The advantage of using Armaflex instead of something like resilient channel is that the wall is stiffer than resilient channel but still isolated. I performed a simple experiment, just holding my ear to one stud wall and tapping the other stud wall (in a normal double-wall construction, 2x4 studs spaced 1 inch apart). Then tap the same stud wall. The difference in level s very very great. is this a finall yes that i can use it?.. :) here is a picture that he gave me.. what do you think?... more about it.. just put "armaflex" in the search here in the forum. he wrote about it earlier last year.

here is an update on our progress... The joists are finnaly up! I put a black chair in the exact spot where the "captains chair" will be.. hehe :) so you can see how the CR will look like.... in front will be the live room and on the left will be the dead room.. COMMING UP! The wall framing. ..if you have any suggestions or a list of Dos and don'ts i will be glad! here some more pics:

On the Armaflex - until I have proof of life and specs, I won't recommend it. If you're happy with what you've heard from someone else, and YOU feel comfortable using it, that's up to you. The best I can say is that I would NOT use it without knowing more about it - you're gambling on setting up a resonance that can make your walls WORSE for isolation instead of better. If you do use it, I would stay with the thinner 1/2" stuff and make sure, if you use the fastening method you posted pix on, that you do NOT tighten the lag screws too tight - if you completely compress those rubber top washers, then you've just shorted out your resilient mount and wasted your time. The sleeves in the pic are necessary to keep the bolts from contacting the sides of the holes in the frame plates. Another thing to watch - after the frames are in place, and BEFORE the wallboard goes on, try this; give the frame a firm thump, either with the heel of your hand or (better) a rubber hammer - if it rings at a particular frequency (it will) try alternately tightening and loosening every other one of the lag bolts through the rubber, so each has a different tension on its rubber washer - this may broaden the resonance a bit which would improve the wall performance slightly, at least in terms of ringing. Looks like you have a nice area above your false ceiling for some heavy duty absorption/bass trapping. \ Mainly I would suggest re-reading through some of the REFERENCE section just to make sure you're following the general rules... Steve

You would be much better off just framing those walls normally, and making some sway braces for the tops of the frames - if you will have an inner, false ceiling resting on the tops of the walls, then you may not even need sway braces at all.

can you give me an example how to do that.. my false ceelig is already resting on the big posts i have.. (as you see on the picture..) the outside walls i will just fasten frames on the big posts.. and put isolation etc.. john is helping around design :) in the design forum.. so i wont have baseplates and stuff i think for the outer wall :) the inner double walls i will put them on baseplates and thught of making them go all the way to the top.. (upper existing ceeling) i think you are right with the armaflex thing.. i didn't find any durometer... i could find the life span.. but i don't think it is a good idea also :) aprrove of the following :) : there is a big drywall company in europe called KNAUF.. they are german.. so thir page is german, the one that has all the detailed info. they also have acoustic walls manuals.. but they do not put caulk.. they have some sort of special gypsum/lime/something elsee compound that it is called UNIFLOTT and they have special isolation strips :) maybe that is what i should put under the wall,, here some links.. unfortunatley in german.. but you can see all the pictures and stuff http://www.knauf.de/bilder/katalog/33769/Doku_010/W14.pdf the isolation walls from knauf here is their chaulk and neoprene :) http://www.knauf.de/bilder/katalog/33769/Doku_010/K433_434.pdf unfotunatly again no specs.. but they are a famous drywall company so i think they know what they are using :) check out as well.. they are not so detailed though [/url]http://www.knaufdrywall.co.uk/[url] should i just put what they are putting under the frames? :) a have such an awkward feeling putting all the basplates on tarmat without anything :) Petar

Petar, I've been 'way too busy for my own good, sorry for the delay - One thing that's bothering me about your layout, is that the CAD drawings http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3048 show framing that is common to both sides of your wall between CR and live room - the pix look this way too. For good isolation between these rooms, ALL of the inner wall/ceiling/floor surfaces need to be physically de-coupled from the outer shell - I'm not seeing that, and I'm wondering how you plan to get good isolation if this is true. You are showing your false ceilings for BOTH rooms resting on the same beams, and this will cause FLANKING between rooms. I am posting a very basic concept drawing or two, hopefully these will help you understand the principles of room-to-room isolation better - In the unmarked drawing, gray is mass, yellow is air/insulation, and brown is other - note that for a sound to escape either room, whether traveling to the OTHER room or to the outside, it must pass through TWO leaves of mass - The roof of almost all construction doesn't count when figuring out your mass-air-mass layout; it WILL affect isolation, and not in a good way; however, you can NOT do away with the ventilation requirements for outer roof because you will get rot and mold; so you need to compensate for this third leaf by making the other two real leaves heavier, and possibly adding MORE vents to the roof to lessen the 3rd leaf effect. Inside your two leaf contaiment area, you can add non-sealed false walls or ceilings for acoustic purposes (better sound) - these will also have some negative effect on isolation which can't be helped - best you can do is heavier outer walls to compensate. These inner, false walls/ceilings can attach to the inner containment leaf (the inner gray part in the drawing) - but should NOT compromise the separation between each room's INNER envelopes - each room should have NO contact with its neighboring room that isn't SOFT, like a sway brace. http://www.johnlsayers.com/phpBB2/viewt ... &start=165 Scroll down a ways for a diagram - and a pic of one installed - http://www.johnlsayers.com/phpBB2/viewt ... &start=210 It's the 15th pic down from the top. Hope this clarifies a few things, gotta go for now... Steve

hi, thank you for telling me that after i built the damn thing! :) here is two sollutions! SOLUTION 1 i put neoprene (the one that is under the posts (the heavy one) durometer at least 60) under the joists of the control room (on the frame where the joists of the CR and live room meet.. majbe even better under both joists :) from the CR and the live room SOLUTION 2 I will build anyway the the double wall unit.. mybe i should fasten the CR joists (since they are not so heavy) to the CR framing.. this way i would detach the joists from the framing heavy construction framing.. my other problem is the walls.. it seems that my whole existing framing is connected.. with a "hard connection".. should i look that i try to have the least contact with the isolation walls and the existing framing?? for now my framing is disconected from my existix structure.. but is alltogeather connected.. !! i see that now! maybe you have some ideas what to do.. whithout dismanteling it! :) (it took us 20 days).. so i wouln't go there! hehe Petar