On Tue, 02 Aug 2011 05:03:51 +0000, you wrote: Soundproofing is something that I know a little bit about - just enough to be dangerous.
A smooth surface reflects sound and a rough surface doesn't reflect all the sound and doesn't reflect it in the same way. So a rough cinderblock wall will make things quieter, and a painted cinderblock wall even though it looks nicer will be noisier because all the little holes in the cinderblock are plugged up. Ceiling tiles use this concept with all their little holes. I don't know what ductboard is but I suspect the problems in an engine compartment will be grease and heat resistance. Vibration isolation is important. We've got a 1932 Plymouth where they had something called 'Floating Power' to isolate the vibration of the 4 cylinder engine from the car. The engine was suspended on rubber mounts. When the motor is running, you can open the hood and see the engine just bouncing around, but the rubber mounts keep the vibration from being transmitted to the car body. If you have a sheet of metal that is vibrating you can reduce the noise by putting holes in it. High frequency noise is easy to block. You can even do it with paper in some cases - you just need some kind of box with no holes. Low frequency noise (most engine noise and things like jackhammers) is almost impossible to block because it travels through solids. That's where increased mass comes in. I once did an inspection in a sawmill and to block the low frequency noise the engineer had figured out that they needed a wall 12 feet thick. If you can't afford an expensive engineering survey, I'd say just try things out and see if they work. You might want to borrow a Sound Level Meter from somewhere to check to see if what you are doing is effective. >My understanding is >- Weight (density) wins when stopping sound >- Surface configuration does have an affect on the high frequencies >- You don't want: > 1) Physical contact between the surface receiving the sound and the surface > on on your side of the wall > 2) Any arerobic connection _at all_ between the noise space and your space. > High freqs go through tiny holes, just like mice. > >You need to fill, plug, gasket and caulk the H*** out of your bulwarks. >Electrical wires and plumbing are serious problems; the bilge connection is a >MAJOR problem. Lead/foam work well when meticulously installed; cement board >can work but is harder to install so it is isolated from the quite space. > >Lots on this topic. Google. > >Cheers, Rufus > >> ----- Original Message ----- >> From: Peter Kafer >> Sent: 07/20/11 07:08 PM >> To: [email protected] >> Subject: [Liveaboard] Engine soundproofing >> >> I would like to add insulation and soundproofing to the engine compartment >> on Now or Never!, a Pearson 323. I have access to quite a bit of duct board >> (1 inch thick, foil faced fiberglass insulation). Is there any reason I >> should not use that? How is it different from similar products specifically >> aimed at the marine market? >> >> thanks >> Peter >> s/v Now or Never! >> > >_______________________________________________ >Liveaboard mailing list >[email protected] >To adjust your membership settings over the web >http://liveaboardonline.com/mailman/listinfo/liveaboard >To subscribe send an email to [email protected] > >To unsubscribe send an email to [email protected] >The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ > >To search the archives http://www.mail-archive.com/[email protected] > >The Mailman Users Guide can be found here >http://www.gnu.org/software/mailman/mailman-member/index.html _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
