"I frequently push
the idea of trying the mic rig directly on the ground to see what it
sounds like there." -David
Hi David,
You mentioned this in post several weeks ago. Shortly after, I grabbed a
pair of Crown PCC160's from a local bargain site to use with my HDP2.
It makes a nice kit, with no tripod to carry. I use them right on the
ground, head-spaced, 110=B0 (a little cardboard template) and the imaging i=
s
pretty good, but not yet in Curt's league (where has he been?). I plan to
do more experiments between 90=B0 and 110=B0.
They are noisier than those lovely Senn's that so many of you are using,
but I also took your advice of cataloging noise signatures of several mics
I use at different gain settings, for use with Voxengeo Redunoise. This
works rather well. Now I just need to find something interesting to point
them at!
k
On Wed, Nov 7, 2012 at 10:38 AM, Avocet <> wrote:
> **
>
>
> > I tried looking at the spectrogram first, but I found the low
> > frequencies a bit hard to interpret on it, unlike bird calls, which
> > make nice patterns.
>
> Peter,
>
> Spectrograms are a bit blurry at low frequencies and you don't get
> many waveforms to work on. The thumps show up clearly on the waveform
> display and you can count the waves to get the exact frequency.
>
>
> > Can you please explain "step function"? Is that like a square wave?
>
> It is a pressure wave which makes a fast high or low change and slowly
> returns to normal as with an explosion or sonic boom. Unlike a burst
> of low frequncy waves, it contains a wide range of frequncies. If
> these trigger a resonance like a cavity or resonant windshield, that
> will then form a "boom" sound. Similarly tapping a mic rig with a
> finger is a "step function" and will make any resonances "ring" Same
> way that bells work.
>
>
> > I'm going to have a play with "fixing" them, but I might end up just
> > leaving them in as Keith Smith has suggested. Did you apply your
> > filter to the whole recording, or just to those sections?
>
> My filter was very extreme to see what was happening. The main boom
> frequencies show up on a power spectrum and I would try a bass rolloff
> from about 200Hz. Listen out for sounds that you are prepared to lose
> along with the booms, but I'd leave them in at a lower level. Back to
> an "artistic judgement". Trying to filter out just the booms or
> editing them out would sound messy.
>
> Digital noise reduction is possible, but you have to define a "sample"
> of just what you want to remove. Fiddly. It's easier to reduce the
> non-bird frequencies and select the best bits and call it artistic
> judgement. :-)
>
>
> > Mostly, although I'll have to take your word for things like
> > "stimulated a local resonance".
>
> I should have said "ringing a bell". :-( Was there a slight wind
> blowing which could have been rocking the mic stand? I frequently push
> the idea of trying the mic rig directly on the ground to see what it
> sounds like there.
>
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
>
>
--
Keith Smith
Keith Smith Trio, Northern Lights =96 Altai Khangai - www.keithsmith.ca
Photography - www.mymountains.ca
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