Hi John--
I have experienced some unusual localization with bullfrogs before so
there could even be some call-specific factors involved. I was very
surprised to learn that the Bullfrog that starts at 29 secs was
likely positioned directly in front of the array because its call
most closely matches the Bull calls that start at 7 secs (left) and
12 secs (right) which David reports as likely positioned hard left
and hard right. I'm considering tonal balance and reverberation. The
additional reverberation in the 29 second Bull's calls would be
explained if coming from a greater distance from the rear but sounds
inconsistent with the calls from the front. There's quite a bit of
sonic variety in the sounds from the front; it seems like anything
due to M-S phase would likely affect at least some of these sources
too. The calls at 7 and 12 sound as I would expect them to for hard
off-axis M-S. David might have used high side levels, but the
resulting mix doesn't seem excessively side heavy to me. That is why
I'm thinking it might have something to do with a reflective surface
near the 29 sec caller.
Why am I interested in this mystery plane? If the 29 sec call were
from behind then it might show how David's array is doing a good job
of creating an effective distinction between front and back sound
planes-- something that typically challenges stereo imaging with most
set-ups I'm aware of. Rob D.
At 6:18 AM +0000 6/17/07, John Hartog wrote:
>David - that is a wonderful recording,thanks for sharing.
>
>And Rob -
>It is interesting to listen for the "different spatial plane" aspect
>you mention. I haven't had much experience using m/s yet, but I'm
>wondering if m/s might sometimes create a rift between stereo and mono
>dimensions yielding straight-on sounds that appear as if on a separate
>plane, because the L/R at straight ahead are essentially phase
>canceled leaving only the original m channel at this position. Could
>it be possible that the central mono and the surrounding stereo might
>not be meshing perfectly? Or am I way off with this idea?
>
>John Hartog
>
>
>--- In Rob Danielson <> wrote:
>>
>> At 11:15 PM +0000 6/14/07, wildlifeanalysis wrote:
>> >Hello Rob
>> >
>> >The mic rig I used was an MKH30 and MKH40 in an MS configuration on
>> >a tripod pointed
>> >ever so slightly upward (~15 degrees) into the trees toward the
>> >bird-voiced treefrog's
>> >perches. I decoded in Peak on Mac with an AudioUnits plugin called
>> >Stereo Image Munger,
>> >which is free and effective. I gave the side mic a little more
>> >prominence than I think is
>> >traditional (the mid was at 100% and the side at 60% of full)
>> >because the sound scene was
>> >so encompassing.
>> >
>> >In the recording, if memory serves, the first calling bullfrog is at
>> >about 12 oclock in the
>> >middle of the sound field.
>>
>> I was guessing it was M-S, possibly a 30 and a 60. The bullfrog that
>> starts at 29 seconds seems like its on a different spatial plane from
>> the other sound sources. (I think the same individual is also singing
>> during the initial fade in). Even if other calls are from behind the
>> mics, all of the other calls seem located in the "front" of the
>> stereo field to me. Perhaps the discrepant bullfrog's calls are
>> reflected within the space differently. I'm trying to gather clues
>> about how this effect is produced.
>>
>> >The second responder is at about 4 oclock slightly behind me,
>> >as you said - so the image is a very hard right pan. I have noticed
>> >that since the MKH40
>> >has a cardiod pattern on either side, they are very sensitive to
>> >sounds from behind. I
>> >wonder if some sort of parabola would cut down on this when necessary.
>> >
>> >If you would like, I can upload the raw MS file if you would like to
>> >remix the sound field.
>>
>> That would be interesting to try. Your mix is very pleasant as is.
>> Thanks for the additional info! Rob D.
>>
>> >
>> >David
>> >
> > >
>> >
>> >--- In Rob Danielson <type@> wrote:
>> >>
>> >> Hi David--
>> >> Thanks for sharing the beautiful recording and
>> >> heartfelt account. I'm in the process of a
>> >> location change in response to similar
>> >> impressions.
>> >>
>> >> Your recording makes me curious about the mics
>> >> and the array or rig you used in relation to the
>> >> stereo field and a unique quality in this
>> >> recording. At 29 seconds, a bull frog starts
>> >> calling in the middle-ground. Do you know where
>> >> this frog was located,.. possibly behind the mics
>> >> at "6 o'clock?" At 14 seconds, is that bull frog
>> >> located at about "4 o'clock"--or hard right? If
>> >> you don't mind sharing the info, what type of
> > >> mics & array did you use? Thanks, Rob D.
>
> > Rob Danielson
>> Peck School of the Arts
>> Department of Film
> > University of Wisconsin- Milwaukee
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