WINDOW PROBLEM

I have constructed a double window between my tracking room and control room. One side has 20mm laminated glass the other 25mm each side is not connected to the other. My problem is I can hear electric guitar clear on the other side I was wondering if anyone had any sugestions or answers to why this is happening? Thanks heaps!!

deeds wrote:

My problem is I can hear electric guitar clear on the other side I was wondering if anyone had any sugestions or answers to why this is happening?

Deeds, What is the cavity between these panes? Why do you refer to electric guitar specific? What about other sources? Do you have an idea about the frequencies bothering you? Are you sure the sound comes through the window? No other sound paths? Where is that window build in and how? Describe wall buildup. You must give better descriptions, otherwise it's too much gambling. These panes are serious panes already.

The cavity between the window is 100mm at bottom to 300mm at top as one pane is angled. I have two walls one for each pane and neither window frame touches the other as each room is seperate to the other each wall has 2 sheets of 16mm plaster board on the in side of the room and one room has green glue in between the plasterboard and insulation. I can not hear speech and if you scream you can just hear it but anything louder and you can hear it clearly from the other side. hope this helps thanks

What's the cavity between that wall? How did you get to this 300 mm? Is that frame as good as these panes itself? What did you mean with Green Glue between wall and insulation? I know Green Glue itself. What's the size of that window? Are it mainly the low frequencies coming through? At a first glance (but impossible to know exact without complete understanding of your build-up) I have the feeling that the window panes are OK but exceed the isolation of wall and/or window frame. But the answer can't be better than the question. If I tell that I have a good car, but his speed seems blocked at 55 m/h, a garage guy needs to know more details. In this case people need to know the build-up in order to imagine all possible sound-paths (including flanking if applicable) in order to find the weak link (which are not the panes itself, as it seems). What does you make think it is the window? And isolation is always a matter of degree. There isn't absolute soundproof isolation. Another idea is to measure gross sound isolation, to get a picture of isolation versus frequency.

The cavity between the two walls that seperates each room is 200mm the plasterboard, insulation and green glue is what each of those walls are constucted from That is a timber frame with insulation 16mm plasterboard green glue and 16 mm plasterboard . there is a window frame for each wall which the glass sits on between timber beading around the outside of the two window frames is insulation. each window frame is 5mm apart all the way around the inside. and covered with cloth. there is two solid core doors for each room and they are sealed with heavy duty door seals. The sound is definetly coming from the glass as you can hear it . If I can hear a guitar amp from the control room I could definelty hear a drum. I would like to hear as less as possible or not at all. If a photo would help I could organize it. Thanks heaps

deed it should be good that you take pictures. Your window panes are more than thick enough compared to your wall leafs. I don't think you have edge absorption do you? Pictures will tell more. What I also know is that it isn't easy to localize sound where it's coming from. That works VERY psycho acoustical. Your panes are respectively 50 and 62.5 kg/m2. Your wall leafs ca 22 to 25 kg/m2. I also have the suspisious feeling that your window frame fails. It's not that easy to make a frame respecting the TL qualities of these window panes. You say it's laminated glass. How is that build up? 2 or 3 layers of glass? how many layers and/or thickness of PVB (foil) in-between. Mostly the glass code on your invoice answers that question. Hearing nothing also depends of the masking level of the reception room. I have experience with ultra high isolation rooms. It's not that easy to obtain the "hearing nothing" level with high emission levels certainly in the lows. It's also relative to expect with that wall build-up obtaining a "hearing nothing" level. But that "hearing nothing" is relative of course. At a certain moment you're blocked by flanking as well. If that's the case, or that window frame is too weak then it's better that a guy with some experience has a look locally. Let's hope it's some simple thing, otherwise you need local help. There are measurement techniques able to find the sound contribution of every individual part of the boundaries in a room, hence allowing to track weak spots, or defining the difference in TL of different parts of the same wall (practically impossible with standard sound pressure measurements). But that is expensive equipment, hence mostly handled by expensive guys. This technique is called intensity measurements.

If everything else (walls, etc) is constructed correctly with no possibility of any "accidental" gaps that are letting sound bleed through then you have to look at the window details........are there any gaps within the frame construction, exactly how have you sealed the glass within the frame, etc., etc. Personally, I believe that everything else being done correctly, you shouldn't need to use glass near that thick. 8)

Hi Here are some pictures of my window hope they are clear enough. Thanks deeds

Deeds, Can you adjust picture size. Please read stickies about this. http://www.johnlsayers.com/phpBB2/viewforum.php?f=17 And add a picture (if possible) where a better total overview of that window is and it's surroundings (both sides). Is that wood I see around that Window? How mounted?

Any conduits connecting thr rooms? Any shared ventilation ducts? Is it possible that the glass isn't laminated after all? Is this on an upper floor? Is the ceiling shared?

Deeds, It only needs the smallest gap or weakness in the design and it will act as a conduit for the sound and as I'm having trouble accepting that the 20 and 25mm glass would, if correctly fitted, allow transmission of sound, I have to wonder if the problem isn't within the surrounding construction. BTW, were you advised to use those thicknesses? 8)

It's obviously built wrong. Can you post the plan drawing for the window?