This is an interesting thread.
Last weekend while was setting up to record at the edge of a small lake, I
considered the sounds from the surrounding canopy reflecting off the surface of
the lake. I chose to aim my mics to accentuate the reflections across the
lake. The height of my microphones were about 6' plus a few vertical feet up
the bank from the water. Had I experimented closer to the ground, might I have
found a sweet spot where the primary reflections better supported the direct
sounds? Maybe, but that tripod does not easily go there.
As has become clear from these discussions so far, there are many factors to
consider when determining the best height for a recording:
- sound horizons
- primary ground reflections
- phase issues
- shadows from ground contours and obstacles
- vertical angle of mic axis
- shelter from wind
What else?
John Hartog
height affects the recording in many ways main obstacle in experimenting with
that is my rigs as the are do not conveniMaybe to find a down low sweet spot
like Curt and Greg have described
--- In "picnet2" <> wrote:
>
> Hi,
>
> I found out this the hard way during a recent beach recording in Portugal. A
> dummy head was used at around 6ft, and then lower to get it out of the wind,
> except the waves caused some pressure difference and "swooshing" as they
> rolled in. Higher up the effect wasn't as pronounced. - sand and with the mic
> low down, plus a slight bank behind the mic were now causing what I
> understand to be some reverberation from the direct (sea in front of the mic)
> vs reflections from the ground and back behind the mic. and my body standing
> about 4 ft away may of also caused some effect.
>
> Side foliage, walls/building, structures under the mic rocks, sand, smooth
> concrete etc. All of these have an effect on reverberation times, and moving
> the mic down may cause changes in the direct to reverberant ratio - in effect
> you are EQ'ing the mic to sound more pleasing to you. All depends on the mic
> stereo recording angle involved and elevation. - Michael Williams has
> written papers on this subject in the past.
>
> BR,
> Mike.
>
> PS Rob, that's the author.
>
> --- In Curt Olson <cro@> wrote:
> >
> > Thanks Greg,
> >
> > I've experimented with ground effect quite a bit over the last year.
> > To my ear, the "fuller sound" you mention seems to become quite
> > noticeable at about 15" or so and increases rapidly to the point of
> > serious ugliness at ground level. But in the 18" to 24" range, there
> > seems to be a certain sweet clarity that seems to drop off ever so
> > slightly as the mic moves upward to about head height -- at least
> > that's what I've ovserved.
> >
> > I've never done any serious experiments with higher elevations like
> > Walt and Dave have done. Hmmm... yup, that's definitely another
> > element to look into.
> >
> > Curt Olson
> >
> > Greg Weddig wrote:
> >
> > > Curt,
> > > I would generally agree with you, though I don't have any evidence
> > > of such. Most of my ORTF recordings are done in that same range. I
> > > think the ground effect most likely provides a bit of a fuller
> > > sound, much like a PZM microphone would.
> > >
> > > Mostly I am trying to keep the mics out of the wind, and keeping
> > > them low I find, depending on the geography, helps shield them from
> > > nearby highway and city noise.
> > >
> > > --greg weddig
> > > http://gregweddig.net
> > > Paradise, CA
> > >
> > >
> > > --- In Curt Olson <cro@> wrote:
> > >
> > >> Ever the respectful contrarian, I've recently discovered -- much to
> > >> my surprise -- that the head-spaced barrier type mic rigs I'm
> > >> currently using seem to render a slightly cleaner image when I have
> > >> them in a "sweet spot" approximately 18" to 24" above the ground.
> > >> This improvement is very subtle, and might be peculiar to my
> > >> current rigs. I'm curious if anyone else has experienced the same
> > >> thing.
> > >>
> > >> Curt Olson
> >
>
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