I used Peel n Seal also. I even went up the back and over the rear dash to keep road noise from coming from the trunk area and went in and covered the interior of the rear wheel wells to keep that noise down. Went up as far as I could on the front fire wall area too.
All those products are waaaay overpriced / hyped. Two ways to reduce noise. Absorb it or reflect it. The road engine noise is very low frequency, and is the hardest to stop the transmission of. It cannot be reflected so it must be absorbed. SHEET LEAD is the best, but heavy! In engine rooms or generators, 1" sheet lead/foam/mylar is used. In music recording studios, very thick 1' or more insulation is used which obviously there is no room for in a car. As a cheap substitute for sheet lead, dense butyl rubber sheet is used. that is what dyna mat is. It is a poor substitute. You can buy this material at Home Depot much cheaper, it just doesnt have a sticky back and a cool Chip Foose Dyna Mat label. First, stabilizing the sheet metal is very important so whatever you use must contact tightly the metal. I used both the 1" Marine lead foam sheet, and a ceramic paint on coating which I built up to 3/4", which I was able to apply in side doors/etc. where the butyl rubber fat mat would be impossible. BTW, the Fat Mat/ Dyna Mat is very time consuming to apply correctly, trust me I've done it. Use two layers of it if you go that way.
Its Noxudol 3101. It can be sprayed but it is a mess. I use throw away brushes and several coats to achieve desired thickness.... it is like painting thin concrete and dries as such. It is water based, but has a very strong ammonia smell so respirator mask is a must. When dry it is like concrete. http://www.soshinusa.com/noxudol.asp (bought from) http://www.maritimeequipment.com/ShowAd.aspx?id=100215 http://www.noxudolusa.com/ http://www.cyber-bridge-marine.com/Engine-Room-Vinyl-Foam-Soundproofing.html other info http://www.allnoisecontrol.com/products/MarineAcoustics/MarineAcousticInsulation.cfm http://www.frontendaudio.com/Auralex-SheetBlok-Vinyl-Sound-Barrier-4-x-10-p/1510.htm http://www.acousticalsolutions.com/audioseal-sound-barrier http://www.soundprooffoam.com/quiet-barrier.html
does/will it crack? Noudol 3100/3101 Noxudol 3100/3101 is a waterborne viscous, elastic sound damping paste based on polymer. Due to its viscous elastic flexibility it converts sound producing resonance into heat...
no crack. crack kills it dries very hard yet is very tenacious, and can flex on sheetmetal. I believe it to be much lighter as well. Sound is vibrating air... vibrations are energy.. reduced to inaudible heat..
