At 7:12 PM -0600 11/15/10, Rick Munday wrote:
>
>
>OK, so I quickly pieced one together yesterday. I'll post a picture or
>two tonight or tomorrow.
>
>I used a Yoga block for the "head", no flashing yet or other foam yet.
>I had two little pieces left when I cut the block to fit into the
>opening and since I had a slight gap on each side between the boundary
>and the yoga block I attached them as "cheeks" on each side of the
>block.
Not sure what you're describing exactly, but as long as the boundary
planes are unobstructed it, should be fine.
Using closed-cell high density foam as a boundary tends to
concentrate more of the boundary effect lift in the 1K-3K Hz range at
the expense of 400-1K Hz and 3-6 K Hz response. Comments on Vicki
Powys last pink noise test in the DIY Boundary Mics blog outlines
some of this. Its not a huge deal, but you might want to try finished
wood or another harder boundary material in your next experiment.
>
>Used two EM172 PIPs as the mic elements.
>
>Mistakes I made:
>
>I screwed up on the measurement for the mic holes (6 3/8" between them
>instead of the 7" called for in the drawing).
That should be okay.
>The "nose" doesn't stick out the full measured distance in the
>drawing, it sticks out 3 1/2" from the front of the wood.
That should be okay.
>
>My jaw hit the floor tonight when I did some test recordings in the
>condo. Very impressive! You get a sense of space, as in up, down, left
>and right that's just insanely good! I can't wait to get out and
>record something outdoors!!!
>
>Now I just have to fill the voids in the back and we're set. Has
>anyone used "Great Stuff"? Or does it need to be a denser material?
The low expansion formula for doors and window will work and is
easier to control. Maybe put a piece of wax paper so it doesn't fuse
to the foam baffle? You just need to close-up the open area but it
doesn't have to be air-tight. I use rubber-backed carpet padding cut
so it fits tight.
>
>I know some of you are used to these arrays, but this is an eye opener for=
me.
>
>Would like to thank Rob Danielson for the plans! This is fantastic!
There are lots of people to thank, actually, including Michael
Billlingsley, Bruce Bartlett, Crown International, Walter Knapp and
Lang Elliot and Mike Rooke. Vicki Powys has also utilized SASS-P
dimensions in her array using two 172's per side that's impressive.
I'll be posting a comparison with her SASS-P MKH-20 mod on the DIY
Boundary Mics blog in a short while. Rob D.
>
>Rick
>
--
"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
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