Hi Rob
Thanks for your comments.
--- In Rob Danielson <> wrote:
> Looks great. Is that a carved wood handle or furniture recycling?
No, I did'nt remove one of the legs from a Queen Anne chair. The
handle on my first home made parabolic reflector looks like this
http://ad2004.hku.nl/naturesound/TomR/PRHSB/handle%20.JPG
In use it is ergonomically less than ideal. I hand crafted the latest
handle from block board. When pointing the reflector to the horizon
this handle is just about at the centre of gravity of the reflector as
a whole. It also has proven useful for velcroing on the power supply
and control boxes.
> It might be confusing folks that the desired sound source you are
> isolating with the dish is pink noise.
Yes, what I was trying to do with the test was to maintain the aim of
the parabolic at a static, constant volume, point source of sound and
then add/reduce the wide stage and focussed characteristics of the
microphone.
> Here's a re-edit that might
> make your success easier to hear. Remember, the pink noise is the
> desired, distant subject:
>
http://ad2004.hku.nl/naturesound/TomR/PRHSB/Three%20Section_Frags_Hinted.mov
>
> (1) the first few seconds is just the wider-image parallel
> boundary/barrier extension in front
> (2) the middle few second is a _mix_ of the above and the below (done
> in the field)
> (3) the last few seconds is just the dish
Thanks for the rework. The test was done at midday in an urban/semi
rural environment with lots of extraneous noise.
> If you can use a distant, natural sound source sitting in the same
> spot for the test, I think people will be able to fully appreciate
> your accomplishment.
Hopefully I will get a chance of doing this soon. A visit to the
Odenwald, the next big forest up from the Black Forest, in south west
Germany is planned.
> Wouldn't it be great to hear it with EM-23 capsules with 14dB(A) less
> self noise? Rob D.
I see from recent posts on the Micbuilders Group EM-23s are available
at primomic.com At about $60 per capsule (100 times more expensive
than the Rapids) I'll have to be sure of my plans etc. before I go
down that route :-)
So, what has been developed (John Hartog's post "Split Parabola Stereo
Array" was my trigger, thanks John) is a single stereo microphone
which operates in a parabolic reflector, in the normal way, to focus
on required sounds. But, it also has the capability of including
during the recording (not added post) the wider environment in which
the focussed sound occurs.
It uses 12 capsules; six in each of the stereo channels. Each stereo
channel has three capsules picking up sound at the focal point of the
reflector, and three capsules on a side of a head spaced boundary
arrangement. The captured volume of the sound at the focal point
(focussed) and at the boundary (wide stage) can be varied relative to
each other while recording.
The only reason for using the capsules in groups of three is to reduce
the effect of the self noise of the very cheap Rapid capsules (search
for "triplets" in the archives of this Group).
Cheers
Tom Robinson
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