2
Date: Sun Feb 25, 2018 10:53 pm ((PST))
Tom:
The idea of clustering the capsules close together is a good one.
But I would run separate wires for the EM-258s because of their worse S/N r=
atio and also since 4 capsules won't work with PIP.
However, I am not sure how ultrasonic mics would perform in a SASS-type bou=
ndary.You need to try it and see if it gives good imaging at very high freq=
uencies.
David Dunn has made some=A0ultrasonic mic boundary arrays that claim to hav=
e unidirectional response, but it is more likely hemispherical in response.
Here is a link:http://subtropics.org/micro-listening-workshops/
He uses an extended range MEMS mic facing a boundary plate about 1 -2 mm aw=
ay.I can't find the build doc online right now, but I have the data somewhe=
re.I'll post it when I find it.
Good luck!
- Gregory
From: " [naturerecordists]" <=
ahoogroups.com>
To:
Sent: Sunday, February 25, 2018 2:50 PM
Subject: [Nature Recordists] Esoteric Mic Builds: Multi-style Capsule SASS
=A0 It's looking like I might have a chance to travel to Austin, Texas, s=
ome time this summer. There are some great opportunities to record Mexican =
freetail bats while I'm there (Congress St. Bridge, Bee Caves, etc.) but I =
don't have much in the way of ultrasonic-capable microphones.
We only have one very rare species of bat where I live here in Hawaii, so I=
haven't had much of a need for ultrasonic mics. I'm more than willing to b=
uild some, but I don't want to pour a lot of effort into a mic I'm going to=
use for a week, and then not need again for years, if ever.
While I was looking at some of the capsules Nick Roast has on micbooster.co=
m, a thought occurred to me: I've got all the bits and pieces to build a du=
al-capsule EM-172 SASS similar to the one Vicki Powys describes on her web =
site:=A0https://caperteebirder.com/?page_id=3D284
If I picked up four EM-258 capsules and either wired them in with the EM-17=
2 caps, or ran a completely separate set of wires, I could potentially buil=
d a dual-range SASS (20Hz-20kHz on the EM-172s and ???-96kHz on the EM-258s=
). The EM-258 capsules wouldn't raise the cost of the build by that much, a=
nd in the end I'd still have an SASS I could use in my largely bat-free env=
ironment here once I'm back from Austin. This would also help solve the iss=
ue of luggage space since I'm going to Austin for a conference and really c=
an't pack gobs of recording gear for the trip.
My thought is to cluster four capsules for each of the two wings on the SAS=
S: two EM-172s and two EM-258s. I haven't worked through the packing densit=
ies in CAD, but I should be able to keep everything pretty close together.=
=A0Does this seem reasonable? Or am I barking up the wrong tree with this i=
dea?
Thanks,
Tom #yiv5632263299 #yiv5632263299 -- #yiv5632263299ygrp-mkp {border:1px so=
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