naturerecordists
[Top] [All Lists]

Re: [Nature Recordists] Re: Infrasound microphone

To:
Subject: Re: [Nature Recordists] Re: Infrasound microphone
From: James Shatto <>
Heh.  I got the MM-1's to IMPROVE the low end.  And they do just that relat=
ive
to the preamps on my Korg MR-1000.  My Avenson STO-2's are still a little l=
ight
in the low end in general, plus high in the noise floor.  I also got the MM=
-1's
to improve battery life by moving the phantom power burden off the field
recorder.  And they do just that.  2.5 hours on fully and freshly charged N=
iMH
batts for the Korg by itself.  2 hours or less if the batts were charged a =
week
ago and left in the off field recorder.  With the MM-1's, in addition to th=
e
Korg, I've done 4 hours continuous and the field recorder still showed 50% =
on
the meter.  Which takes about 30 minutes to go past with just the field rec=
order
and phantom powered STO-2's.

EQ is your friend.  Not really doable at those frequencies live though.  Ba=
ring
some DIY and other custom electronics.  You also need a monitoring environm=
ent
capable of producing those tones to hear what you recorded.  Otherwise you =
might
need to double the speed or more to bring those frequencies up to the
reproducable range depending on your gear.  Audacity has some tools to anal=
yze
and filter and EQ.


Even if your headphones are spec'd to 5Hz, they probably don't actually pro=
duce
that.  And wind noise and other things can be in that range, so there's not=
 much
proofness in such content.  Although using that range as a location detecto=
r
might be interesting.  Those lower frequencies don't travel as well over
distance in air.  Visions of indians with their ear to the ground come to m=
ind.
I guess I should have done more school.  It's feasible to make a locator wi=
th
three points in contact with the ground.  Strength and timing to each senso=
r
(mic) to determine a direction.  Much like earthquakes and the use of three=

points to determine the epicenter.  I'm not sure how useful it'd be without=
 hard
data to single out the subject from deer, bear, squirrel, wolf, wildcat, mo=
ose,
and whatever other critters.  It's a noisy world out there.  And you'd only=
 be
able to detect when the subject was moving.  And trying to find / catch up =
with
a moving
target might be an exercise in futility.

I've had SM81's that were decent on the low end.  No measurements though.  =
Just
a hankering for some Tuba.  An old AT4033a was pretty sweet on the low side=
.  A
current AT3035 that is okay down low.  Noticeably better than my STO-2's.  =
None
of which I'd want to use outdoors since wind proofing them would be near
impossible.  Plus you need some decent shock mounts or it's all handling no=
ise.
Special cables and other things to further isolate them from the rigging.  =
Good
luck with that as that range is probably the most difficult to do well.  I'=
ve
been longing for some MKH8020's which spec okay down there according to the=

manufacturer anyway.  But not cheap, and not the most favored of the not ch=
eap
mics.

- James

--- On Wed, 7/28/10, Eric Benjamin <> wrote:

<Prev in Thread] Current Thread [Next in Thread>
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU