Starting to worry - your thoughts guys

I have just finished the first layer of plasterboard on the control room side of my double wall system. I need to mud and tape this and seal all perimeters with mastic. The tracking room wall is an inside out wall on rubber pads top and bottom. You can see this in the door wayon the photo. The control room wall is a normal stud wall connected directlly to the floor and ceiling with nails. You can see this in the photo I noticed that if I hit either wall with my fist that the other wall vibrates. Both walls are insulated as you can see and the insulation does touch but there is no other direct contact apart from I suppose the common floor and ceiling even though the tracking room walls are seperated by rubber matts. I know that slamming a wall with my fist is not normal practice but should i be worried that the vibrations seem to go from one wall to another very easily? I am thinking kick drum here!! Thanks -I suppose it's to late anyway but some peice of mind would be nice!! JG

Air pressure, if you hit one wall you are creating air pressure vibrations so the other will vibrate, the issue is how much SOUND TRANSMISSION LOSS is there..... SO some vibration is normal.....Especially with only one layer of drywall :) That is why you go for multiple layers, this reduces the amplitude of the vibrations... So when you get to your 2nd or third layer let us know. LOL I have 2 layers of 1/2" and 1 layer fo 5/8 In My Live room and 2 layers of 1/2" in my Control room.

Thanks Bryan, I will get this one sealed up, add another of 5/8 and see how we go. It's no biggie to add another third layer if I have to I suppose, it's a small wall, only four sheets ($100) needed!!. I,m already double budget anyway!! :evil: :cry: Thanks for the quick reply JohnG

Yeah fear not..... Remember dont make the layers the same thickness. if you did trip layers perhaps like this 1/2, 1/2, 5/8 on one and 1/2, 1/2,1/2 on the other....

There's been some debate on the "use multiple thicknesses" around here though... While there are some advantages to using different thicknesses, there is lost opportunity to use all of the same "thickest" thickness, which equates to more mass. :roll: John, have you considered trying to get your hands on some Green Glue? They have distribution in Europe now. I don't know if it's available in your part of the world or not though... :?

Hi Bryan My live room wall is already done, this is only one layer of 5/8 with fluffly insualtion on the back and rigid insulatuion on the front (inside/out design). I can't add more mass to this. I am now working on the control room side which will be either two or three layers. (I think two will be OK for me I hope). The system will have a total of three/for layers. I was told that one layer on one wall and three layers on another wall produces the same result as two on each side. It was easy to make the inside out wall just one layer. Thanks guys JohnG

is it a weight issue why you cant add another layer of Drywall???? Even a 3/8" layer??? My concern is overall stiffness of that layer.... I am not sure of all the theory floating around (I am known as the guy who tried it and relayed wether it worked or not....1 layer seem quite ineffective to me. I had 2 layers in my CR and 1 in the Live room and fired up the monitors to see what happened. When I added the last 2 layers I could Crank My monitors and not hear a peep in the live room . Not sure of you situation but I would do no less than 2 layers if you can. If you cant, ignore me. Ford Uses CAD to build cars and they still have massive recalls. :)

Hi Bryan, As you can see from the original photo the tracking room wall is already done. I can't add anymore wall board to it as it is has another new wall in front of it now. I would have to rip this wall down and start again. (remember the tracking room walls are inside/out so the wall board is on the back, not the front). also, The other three walls of the tracking room were only one layer due to weight problems lifting them into place and also monetary issues. There was no point making the wall along this section between the two rooms two layers when the other three walls had only one layer. Thanks JohnG

Yeah, he's doing an inside-out wall thing. :roll:

Actually there is a good reason to do so, but I see your point. My Live room Wall between my CR and Live Room is 3 layers whereas the other 3 walls are 2 layers (in the live room) My Studio is on the 1st floor of a house so my #1 external sound control concern was Mr. BoomBox in his Truck. Those Guys are not heard :)

I have always thought as a massive last resort that I could beef up the single layer tracking room walls with another layer from the inside in between the studs. A bit of work but so be it. Anyways I will get the two layers up in the control room, do the doors and windows and see where we are. There is a wall chart floating around that showed the difference in three layers to four layers. It was not much. 4-6db I seem to recall. I am aiming at about STC 55 for the room so I think that this double wall with one layer one side, two the other should do that OK as long as evverything is sealed well. :roll: Thanks guys JohnG

All I can say is go for it. :) 2 and 1 might work well. COnsidering I dont do drums everyday it is not that critical for me (though that is starting to change.....) I have done 3 full band sessions in the past 4 weeks. (multi-day sessions)

John, Didn't you say that the control room walls are anchored to the floor AND ceiling? That's not a good thing. Is it possible that the wall to wall vibration is going through the ceiling joist? len

len-morgan wrote:

John, Didn't you say that the control room walls are anchored to the floor AND ceiling? That's not a good thing. Is it possible that the wall to wall vibration is going through the ceiling joist? len

Totally not good at all, At worse case you have closed in the ceiling and are using neoprene to isolate the wall from the ceiling....

Len/Bryan, his walls are kind of "wedged in" with rubber on the top and bottom... :roll:

That should help a little bit. I recall a company back in 1996 that built a studio in that fashion... Difference was they had 24" of space between rooms.....

Guys, I do think that some of the problem is that both rooms share the same commom floor (floor joists) and also the same common ceiling (ceiling joists). I used rubber top and bottom on the live room walls to somewhat isolate them from the shared floor and ceiling but there is still some hard connection in the the live room ceiling via the hat channels that are connected to the shared ceiling joists and in the live room floor via screws that hold the new floor down on the existing floor. There was no way around this unless I wanted to basically work as a hunch back and float a totally new floor and ceiling. There was also no other way I could see to connect the new control room wall to the existing structure apart from nailing it into place directlly to the floor and ceiling. My feeling is that when I hit either side of the walls that seperate the control room and live room that some of the movement/vibration I see is air pressure but some is also the unavoidable connection of a shared floor and ceiling. I suppose the question is once the new control room wall is totally built and sealed how much energy created in the live room will transfer though this shared floor and ceiling via joists/rafters etc. Hitting the wall with my fist is at the extreme end of the spetrum I would have thought compared to a gtar amp or drum kit. The interesting thing is that I have been insulating the live room walls over the last few nights with 50mm semi rigid insulation (705) and it really makes a huge difference to the transfer of any vibrations even when you hit the walls really hard with your fist. I have not done the control room section of the live room yet but I am hoping that it will also make a perceviable difference to the "solidness" of this wall section on the live room side anyway. I have no choice but to proceed with the control room side of the double wall by adding another one/two layers too increase the mass, sealing all the seams and making sure the window and door seals are nice and tight. Thanks and any other comments would be appreciated. JohnG

TRhere are always some compromises when retrofitting a house.... Some thinsg may not be ideal, but still reasonably effective.

Thanks Bryan, you just made my day. It's nice to have some positive comment. I realize that I have made compromises but hopefully nothing to "life threating" Keep you posted JG

Sometimes we can be so perfectionistic (the assumption is if you caome here you want it perfect) but we realize workarounds. I had to do woararounds in my studio stuff I wish I didnt have to do, but cost and structure dictated I had to make compromises. But we endeavour to alwasy give a best case scenario...

John,

JohnGardner wrote:

Thanks Bryan, you just made my day. It's nice to have some positive comment.

I'm sorry if my comments came off of critical or discouraging. That was certainly not my intent and I think I speak for most people here in that regard. I had forgotten that you had the foam at the top and bottom of the walls. I latched on to the "how tightly wedged in the wall was" comment and jumped right to "nailed together." I hope we can be forgiven for (prematurely) jumping on this. If you have been in this forum for any length of time, you see countless people who say something to the effect of "I don't have the money, space, time, talent, whatever to do it right so I did it wrong. Now how to I make it perfect." Except for those with unlimited budgets, everyone of us makes compromises in our projects. Some times the rationale is reasonable. I my case for example, floating the floor of the rooms was not deemed necessary because isolation is not an issue for me (solid outer building, no neighbors, etc). Would I like to have had a floating floor, yes. But my building didn't need it for isolation, and my ceiling height didn't really make it practical. Could I have removed the roof of the building and put on a pitched roof which would have given my the height? Yes. But budget didn't allow. Also, it seems that lots of people get wrapped up in the isolation issue and forget the practical realities. For example, I can't see any scenario where I'll be mixing FINISHED tracks in the control room while I'm recording a band playing in the main room. I'll record, then I'll mix. Therefore, I don't need to have so much isolation between the control room and main room that the band looks like they are doing pantomime (sp?) when in reality they are "dialed to 11." If I had thought about how I was actually going to use the rooms at the design stage, I think I still would have used double walls and two layers of DW all around. The other reality we all have to deal with is that the STC ratings we are all trying for are a lot like the government milage ratings on cars: Your milage WILL vary! :-) The walls that are used to come up with those numbers are built by professionals and tested in labs. We will be lucky if we get close to those numbers so I'm happy to over build a little. I'm sorry, I started to ramble a little. I didn't mean to hijack your thread. len

len-morgan wrote:

Also, it seems that lots of people get wrapped up in the isolation issue and forget the practical realities. For example, I can't see any scenario where I'll be mixing FINISHED tracks in the control room while I'm recording a band playing in the main room. I'll record, then I'll mix. Therefore, I don't need to have so much isolation between the control room and main room that the band looks like they are doing pantomime (sp?) when in reality they are "dialed to 11."

Till you are cutting drums and the phase cancellation of the drum sound passing through the wall messes with what your monitors are putting out :)

Well, I'm not proposing that we all give up and use wall paper instead of dry wall. In the case you mentioned (drums) while it's not optimal, couldn't you record a little, stop playing and listen to what you've got, make adjustments, then record the whole thing? Yeah, it's not perfect but again, we don't have unlimited budgets so we need to work with what we have. len

Great post, Len. :-)

Len, would you pay an engineer to work as you suggested. set up mics, record stop/listen record some more, stop listen adjust mics??? I prefer to adjust mics prior to hitting record. I rpefer to get good quality tones and levels before we start recording takes..... Just the way I was trained......Not etched in Stone...... We may not have unlimited budgets but we dont have unlimited time either....