At 4:30 PM +0100 11/22/09, Klas Strandberg wrote:
>
>
>Developing the Murie Mike, I sent a file "Grinden091122_edit.mp3 "
>to our site. It's a "everyday" recording of birds, distant traffic,
>neighbors working and horses running. Comments on
>stereo width and "space" is very much appreciated.
>
>Klas
Hi Klas--
I really like your product idea of a pocket recorder compatible,
hand-held stereo mic array for optimized spatial imaging. (For those
who haven't looked at an earlier version of it yet:
http://www.telinga.com/gallery/MurieMike%20009_sm.jpg )
After listening to the M10's built-in mic array this morning, I was
immediately struck by the enhanced spaciousness that your spaced omni
array affords. In order to explore its tonal balance and stereo
imaging qualities, I took the recording through some mastering and
noise reduction processes*. After reducing some of the mechanical
drones in the setting, I found that increasing the volume of the
center seemed to help with a sense of depth and articulation of
sounds across the field. (*As with the M10 recordings Raimund has
been making, I used stacked effects "plugs." I used one L/R -> M-S
plug to convert the stereo to M-S, followed this with a parametric
equalization "plug" to control the tonal balance of the center and
side channels separately, and, finally, I converted this back to
normal stereo with a M-S -> L/R plug).
Here's a QuickTime Movie with original recording first and
Center-Boosted/Equalized modified version next. The movie soundtrack
is loud, be sure to adjust playback volume to your taste:
http://tinyurl.com/y94lk3z (2 mb)
or the full link:
https://pantherfile.uwm.edu/type/public/temporary/MurieMicLS-10Flt_BoostCnt=
r_Sor3AAC256.mov
Not QuickTime compatible? Here's the .wav file only with the change
from the original recording to the modifications occurring about 19
seconds in:
http://tinyurl.com/ydj8njp (7mb)
And the associated Mid-Side and Equalization modifications used as a
still photo: http://tinyurl.com/ydda3em (download jpg). The red area
in the parametric EQ window represents attenuation made to the "mid"
channel and the blue area represents attenuation made to the
"sides"channel. The gray area under the white, "0" line is
attenuation on both the mid and side channels.
I listened to the recording on my speakers only, not with headphones.
I felt like the stereo imaging was giving me a pretty good sense of
the location. Most of the treble content from the setting seemed to
emanate from the areas around the two speaker except for louder,
treble elements like some of the bird calls and the wing-flutter-pass
which took-up "phantom" positions between the speakers. The lower
mid-range (125 to 700 Hz) mechanical drones from the environment were
mostly centered in the stereo field in the original but subtle phase
and tonal differences between the bass on the sides kept it from
homogenizing into the center. The recording was quite responsive to
EQ adjustments and I could position the city drones and workshop
sounds more clearly after the changes. The lowest octaves seem a bit
weak which could be a product of the recorder. There was some noise
in the lower mid-range that I suspected could have been from the
recorder pre. Was a LS-10 recorder used perhaps?
If I were to imagine improving the performance of the stereo array, I
would start with exploring ways to spread more of the softer treble
content across the middle (a familiar challenge). Are the diaphragms
of the mic capsules flush with the skin of the plastic material? If
so, I'd try mounting the capsules on the skin facing forward
(positioned with mic diaphragms perpendicular to the skin, not
embedded). With both capsules nearly parallel and facing forward, the
head-like barrier might work better if the sides are flattened more
like the sides of our heads. This will also help preserve ear
spacing. I don't think there's as much one can do about the centering
of the bass content, but, if one wants to get fussy, this tendency
was pretty effectively reduced with the L/F -> MS -> Cut Lower
Mid-Range EQ -> MS -> L/R adjustment.
Thanks for sharing your project with us and for the chance to provide
some feedback. Rob D.
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