At 4:45 PM +0100 12/15/09, Klas Strandberg wrote:
>
>
>The hole is a consequence of the two mikes, boosting HF sideways and
>can only (...?) be heard (in a bothersome
>way..?) when you record awidespread "sparkle all
>around" as when the grain snow hit the frozen
>leaves in this almost panorama way.
>
>A more "common" stereo picture is at the the ending of
><http://www.telinga.com/gallery/tripple_birdfeed.mp3>http://www.telinga.co=
m/gallery/tripple_birdfeed.mp3
>where you don=B4t
>clearly hear the hole, as there are no audible HF getting boosted
>from the sides. Birds are flying between the feeder and a tree at the
>left, and I don't hear any bothersome change of wing sounds over the area.
>I have tried out a prototype where the mic capsules point forward,
>not to "shade" themselves, but then I loose some of the "crispiness"
>that I like and that so easily can be filtered, then also reducing
>some of the mic self noise.
Of course, all stereo arrays have draw-backs and
one's preference can depend on what one considers
to be more natural, more striking, more accurate,
etc.
Some listeners prefer the additional HF contrast
between the LEFT and RIGHT speakers because it
gives a sense that the sound horizon has more
spread. However, even omni mic capsules are
slightly treble-centric-- the "center" of their
polar pattern is more sensitive to HF than the
sides (usually). When the mic capsules are
directed out or (opposing) towards the sides, the
LEFT speaker and RIGHT speaker contrast is
heightened. In directing both capsules straight
forward, (oriented perpendicular to a flat
boundary or tangential to a spherical or curved
one), the center of the field is rendered with
more HF emphasis. Moving the capsule diaphragm
out of the pressure zone tends to simplify the
"cues" as the capsule is no longer in the
"pressure zone" that comes with mounting the
capsule with the diaphragm flush to the boundary.
There are many opinions about the plusses and
minus's of capsule orientation. I personally
feel, given the effects of the options, that
front-facing capsule orientation is more
"natural" in that it establishes a "front stage"
where sounds become symmetrically darker as they
move towards the sides. The head-spacing/timing
differences are preserved and there is plenty of
LEFT - RIGHT contrast and horizontal spread. (One
stereo array with flush-mounted capsules that
seems to be an exception is the SASS. I've never
been able to do side-by side comparisons with
one.)
Creating a HF boost in the center of the stereo
field has other advantages. Traditional EQ
affects center and side tonality _at the same
time_. If one uses standard parametric EQ to
reduce extra crispness at 4K Hz from hard left
and hard right, the crispness/tonality of the
center is also lessened. I think better overall
side-to-center tonal balance after EQ can be
achieved with forward-facing capsule orientation.
>If "State of the Art" measurements + a good middle is required, only
>the best M/S system will do and then we enter into another world, you know=
.
>Still, I must say, - I have heard professional M/S recordings which
>have been less "alive" than from binaural and semi-binaural set-up's,
>some M/S has even been "flat".
Some listeners prefer a very EVEN stereo field
where the sounds are more closely positioned
across the middle. Coincident stereo arrays like
X-Y and M-S can do this (though the later needs
to be carefully adjusted). These arrays tend* to
have less left-right contrast and with the X-Y
array, sounds can feel bunched together in the
center. With M-S and X-Y there is no timing
difference analogous to the spread of the ears
and no baffle or boundary cues produced as with
our heads. *Note many recordists that use M-S
rigs tend to lower the level of the center mic to
create more left right contrast.
There's another way, in post, to adjust the
tonality of the Center and the Sides of the
stereo field separately. It involves using "plug
ins" in the mixing chain. We first discussed
this technique in this list a year or so ago.
Here's a screen shot of the chain I've been using:
https://pantherfile.uwm.edu/type/public/media/MixingChain_EQBetweenM-SPlu=
gs.jpg
I've been mixing material generated by a number
of stereo arrays over the past few weeks and
sometime this technique works very well and other
times not. I'm looking for patterns. Rob D.
>
>Best wishes from Klas and a snowy Sweden.
>
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