Hi Peter,
The open cell foam in the nose baffle is part of the original Crown SASS de=
sign, and that design has proven good for natural soundscape recording. I t=
hink the reason for sticking with the open cell design is mostly for the sa=
ke of consistency. Some low frequencies will pass through the foam nose, so=
me frequencies are absorbed, and some will be reflected. The qualities of t=
hese transitions will depend on the specific material used.
John Hartog
rockscallop.org
--- In Peter Shute <> wrote:
>
> I'm building a SASS array to Rob Danielson's design (https://pantherfile.=
uwm.edu/type/www/audio-reports/BoundaryMicExperiments/images/PBB2N-Plans_SA=
SS-LikeDimensionsSept2010.gif), and I have some questions about the foam us=
ed for the nose (baffle?)
>
> The plans say to use high-density open-celled foam, and I don't know how =
to identify the stuff. I rang the local supplier (Clark Rubber, which Austr=
alians would know), and they said they can cut a piece for a few dollars. B=
ut when I mentioned what it was for, they said it would be better to use ac=
oustic foam, which doesn't cost much more.
>
> They said it's similar, but denser. It also comes in thinner sheets, so I=
'd have to glue two pieces together.
>
> Will it be better. Does it even matter?
>
> If the aim of the foam is to block sound from the other side, why open ce=
ll? Does it work better for that?
>
> Sorry if these are basic questions, I don't know anything about foams, th=
eir acoustic properties, and how this array works.
>
> Peter Shute
>
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