Ron, I believe my thought, as I understood the reasoning, was that if the way the wall was built reduced the sound by 50%, then splitting the plates might add another 10% and be noticeable. If the other factors in the wall are done properly and the noise reduction reaches 90%, splitting the plates has far less of an effect on the overall noise reduction and is not important. By the same token, if the soundboard rib structure etc., is designed to achieve the desired stiffness, the bridge stiffness becomes a non factor. I hope that's what you guys meant, thanks for your polite response. On the soundproofing, fiberglass does have sound deadening properties but takes up too much space in comparison to other materials and is hard to eliminate holes. Since you pay by the square foot as measured from the outside of the building, what you take up on the inside with your walls and such can be expensive. If your walls are not structural and are basically there to divide space and hold up the sheetrock, I wouldn't frame it with any more than a 2 x 4s or even less. In the condos I have worked there is no fiberglass in the walls between units. It's considered a waste of money. Keith ----- Original Message ----- From: "Ron Nossaman" <RNossaman@cox.net> To: <pianotech@ptg.org> Sent: Wednesday, August 07, 2002 9:48 PM Subject: Re: OT: Question on Lesson Studios > > > I've been in the construction trades for 30 years and > >only a few times have I ever seen the top and bottom plates split. This is > >because they are nailed solid and any sound transmission is through them and > >not due to the outside surfaces of the wall acting as one unit. It does have > >some effect but when the rest of the wall is built properly it is > >negligible. I think that is the same argument Del and Ron use for not gluing > >the bridge on the soundboard in the crowned position. > > > I'm not sure where this connects. Splitting a wall with sheetrock attached > to every other stud from each side works by de-coupling the two sides of > the wall, so the movement from one side doesn't directly move the other. > Sound deadening panels do essentially the same thing. The movement of the > surface picking up sound vibrations is absorbed and dissipated within the > non-rigid interior of the panel instead of mechanically moving the opposite > surface along with it. If the perimeter of the wall is anchored in > something either massive or absorptive, instead of another elastic membrane > like the wall surface, it shouldn't be a big problem. You lost me on the > bridge, soundboard analogy. Where's the connection (as it were) there? > > Trying to keep up. > > Ron N > >
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