Most of the knowlege which I got from this and similar forums says that closed cell foam is the typical material used as the decoupling layer for the sound barrier layer (typically mass loaded vinyl) and that CCF does little on its own to block outside sounds from entering the cabin. Another benefit of CCF for automotive use is water impermeability.
But I live in Europe, and in most non-English (German, Polish, Russian, etc.) European forums, online specialist shops, manufacturer web sites etc. the typical material used is OPEN cell foam, not closed cell foam.
Moreover, anybody over here rarely uses a thirs, heavy sound blocking layer (as MLV).
Most folks in "audio hifi" circles and even in specialist sound deadening material shops don't even have an idea what MLV is.
So, the typical complete sound deadening and vibration damping treatment which is professionally advertised and applied in many places in Europe consists of only two layers:
1. CLD (alubutyl)
2. OCF - open cell foam
And that's it.
Don't believe me? Check out the offerings from European manufacturers like SinusLive, CHP, CTK, Pimp My Sound, Variotex, Ground Zero ....
My questions are:
1. Did these European manufacturers and professional installers figure out a more effective, cheaper and simpler solution for blocking the outside sounds from entering the vehicle cabin - that OCF replaces and outperforms both CCF and MLV combined?
2. What would be the (dis)advantages of using OCF instead of CCF in any place and role inside a vehicle?
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