If I can re-open this thread,
I'm still unclear about exactly what high-density open-cell foam is. My loc=
al building supply store hasn't a clue.
I have several types of foam lying around the house.
1) One is very soft and pliable, like the foam windscreens that come with m=
ost microphones. It came as packing material.
2) Another is a bit denser and thicker, the sort of foam that is used for m=
attresses.
3) Then we have what in the USA is called blue board. This is a very dense,=
small cell, rigid foam that comes in sheets of various thicknesses and is =
used for building insulation (we have some left over from insulating our ce=
llar). Sort of similar to styrofoam.
4) Finally I have sort of an odd thing that came as cushioning material in =
a box with an electronic device. It is rigid, like the blue board, but the =
cells are much larger than that in the blue board and therefore it is a bit=
springy when pressed. It is not as rigid as styrofoam.
5) Oh, and somewhere I have a block of stiff, small-celled foam that is use=
d to go between a kayak or canoe and the roof of the car.
Are any of these "high-density, open-cell" foam? If not, what does this cre=
ature look and feel like?
I built a prototype sass array using EM172 capsules, and #4 above for the n=
ose baffle, and it works well as far as I can tell, but for the real thing =
(built for AT3032 mics), I'd like to get it right.
Many thanks!
John
John Crockett
Westminster, Vermont
--- In Peter Shute <> wrote:
>
> I made it to Clark Rubber tonight, and sure enough it wasn't as I expecte=
d. According to this store, high density foam comes in colours, and acousti=
c foam is grey and only 2" thick.
>
> Then I spotted a light grey scrap in a bin, exactly the size I wanted, bu=
t twice as long. It felt like the acoustic foam, so I think it's the right =
stuff. They weren't sure what it was and thought a customer had left it beh=
ind after bringing a piece in for cutting, and let me have it for $3.
>
> There's something a bit disturbing about an industry that's inconsistent =
about what it calls its products.
>
> Peter Shute
>
>
> --------------------------
> Sent using BlackBerry
>
> ________________________________
> From:
> To:
> Sent: Tue Feb 28 10:17:03 2012
> Subject: Re: [Nature Recordists] Re: Foam for SASS
>
>
>
> Peter,
>
> re filling inside of SASS box - well I've overcome that problem by
> making my SASSes out of solid blocks of closed-cell foam (it's
> lighter weight too) - see my website. If you've made a wooden SASS
> you could fill the gap with closed cell foam.
>
> Vicki
>
> On 28/02/2012, at 9:08 AM, Peter Shute wrote:
>
> > Excellent, if I can tell by colour then they can't trick me. It
> > sounds pretty cheap, so I'll get enough for future experiments.
> >
> > Can you recommend what to fill the inside of the box with?
> >
> > Peter Shute
> > ________________________________
> > From: <naturerecordists%40yahoog=
roups.com>
> > <naturerecordists%40yaho=
ogroups.com>] On Behalf Of vickipowys
> > Sent: Tuesday, 28 February 2012 8:54 AM
> > To: <naturerecordists%40yahoogro=
ups.com>
> > Subject: Re: [Nature Recordists] Re: Foam for SASS
> >
> >
> >
> > Yes Peter, Clark Rubber call their stuff 'high density foam' and it
> > is grey in colour (as opposed to medium density foam which comes in
> > many colours). The acoustic foam is black. My nearest Clarks used
> > to be at Bathurst (2 hours away) but they closed and now I have to
> > get it via mail order from Dubbo where they can never cut it
> > straight. I agree Clark's website is pretty useless. If you can get
> > Clarks to cut it in blocks around the size you want, you can then
> > taper the sides according to Rob's specifications, using a razor
> > knife with a new blade extended all the way out. And tidy up the cut
> > surfaces with a little piece of fine sandpaper.
> >
> > Vicki
> >
> > On 28/02/2012, at 8:17 AM, Peter Shute wrote:
> >
> >> Thanks, Vicki. You mean the one they're calling high density but
> >> which isn't acoustic foam? If that works then it would be better
> >> not to have to glue it.
> >>
> >> It's a pity I can't see the stuff on their web site before I go
> >> there, or even just order it online to save myself the trouble, but
> >> the web site is a mess. A search for high density foam takes me to
> >> anything but what I expect to see.
> >>
> >> Peter Shute
> >>
> >> ________________________________
> >> From: <naturerecordists%40yahoo=
groups.com><naturerecordists%
> >> 40yahoogroups.com>
> >> <naturerecordists%40yah=
oogroups.com><naturerecordists%
> >> 40yahoogroups.com>] On Behalf Of vickipowys
> >> Sent: Tuesday, 28 February 2012 8:06 AM
> >> To: <naturerecordists%40yahoogr=
oups.com><naturerecordists%
> >> 40yahoogroups.com>
> >> Subject: Re: [Nature Recordists] Re: Foam for SASS
> >>
> >>
> >>
> >> Peter,
> >>
> >> I have always used the grey high-density foam from Clark Rubber,
> >> which is fairly close in texture to the original foam that was used
> >> in the Crown SASS design. And you won't have to glue either.
> >>
> >> Vicki
> >>
> >> On 28/02/2012, at 7:28 AM, Peter Shute wrote:
> >>
> >>> Good enough for me then. I'll try to get there tonight and get some
> >>> of the acoustic foam.
> >>>
> >>> The plans also say to fill the void with "dense absorptive material
> >>> like rubber backed carpet padding". Does that mean similar material
> >>> to that used for the baffle? I.e. can I just get a bit more of it
> >>> to put in there?
> >>>
> >>> Peter Shute
> >>>
> >>> ________________________________
> >>> From: <naturerecordists%40yaho=
ogroups.com><naturerecordists%
> >>> 40yahoogroups.com><naturerecordists%
> >>> 40yahoogroups.com>
> >>> <naturerecordists%40ya=
hoogroups.com><naturerecordists%
> >>> 40yahoogroups.com><naturerecordists%
> >>> 40yahoogroups.com>] On Behalf Of hartogj
> >>> Sent: Tuesday, 28 February 2012 7:19 AM
> >>> To: <naturerecordists%40yahoog=
roups.com><naturerecordists%
> >>> 40yahoogroups.com><naturerecordists%
> >>> 40yahoogroups.com>
> >>> Subject: [Nature Recordists] Re: Foam for SASS
> >>>
> >>>
> >>>
> >>> Hi Peter,
> >>> The open cell foam in the nose baffle is part of the original Crown
> >>> SASS design, and that design has proven good for natural soundscape
> >>> recording. I think the reason for sticking with the open cell
> >>> design is mostly for the sake of consistency. Some low frequencies
> >>> will pass through the foam nose, some frequencies are absorbed, and
> >>> some will be reflected. The qualities of these transitions will
> >>> depend on the specific material used.
> >>>
> >>> John Hartog
> >>> rockscallop.org
> >>>
> >>> --- In <naturerecordists%40yah=
oogroups.com><naturerecordists%
> >>> 40yahoogroups.com><naturerecordists%
> >>> 40yahoogroups.com><naturerecordists%
> >>> 40yahoogroups.com>, Peter Shute <pshute@> wrote:
> >>>>
> >>>> I'm building a SASS array to Rob Danielson's design (https://
> >>>> pantherfile.uwm.edu/type/www/audio-reports/BoundaryMicExperiments/
> >>>> images/PBB2N-Plans_SASS-LikeDimensionsSept2010.gif), and I have
> >>>> some questions about the foam used 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 Australians would know), and they said they can cut
> >>>> a piece for a few dollars. But when I mentioned what it was for,
> >>>> they said it would be better to use acoustic 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 cell? Does it work better for that?
> >>>>
> >>>> Sorry if these are basic questions, I don't know anything about
> >>>> foams, their acoustic properties, and how this array works.
> >>>>
> >>>> Peter Shute
> >>>>
>
>
>
>
>
>
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