At 5:46 PM +0000 10/6/10, hartogj wrote:
>
>Hey Rob,
>
>> Not as a criticism but to point out one trait
>> that people cite as a positive with Jecklin disks,
>> it is the continuous, lower frequency/background
>> sounds that are well-represented at the edges of
>> the stereo field. Wind in the pines is a good
>> example. Take a listen to your recording on
>> speakers. Does it seem as if the wind is coming
>> out mostly from the locations where the speakers
>> are located? If there little or no wind more
>> accurately imaged in the center, how can this be
>> a good thing?
>
>I think this is a result of folding of hemispheres. Could it be that
>widely uniform sounds directly to a side get folded on themselves
>thus summed?
Hi John--
By "fold" are you referring to possible reflections from the barrier
back onto the mics? With a distance of ~ 6" from the mic to the
barrier, its theoretically possible that waves could sum or
double-up. It would be much higher in the spectrum than lower mid
range-- around 2200 Hz (13600 inches/second / 6"). The spread
between the mics would have to be a minimum of 27" for sound waves
coming from opposite sides to double-up at 500Hz.
With far field recording, I assume there are many, similar amplitude,
somewhat harmonically related sound waves converging on any point in
space from many directions. The further the mics are spread, the more
variation there is between the two points. I've noticed that the
bass separation effect kicks in at about 11" outside with free air,
spaced, omnis. To improve on this sketchy understanding, I'd have to
dig into papers like those Paul J. is reading. :-)
I assume that the lower register sounds that collect in the middle
are long waves that wrap around/elude the presence of the baffles and
place both mics under very similar influence.
>Even with the perfect configuration, that will still remain only one
>array in an array of arrays useful for creating a meaningful variety
>of perspectives.
Once we get better understandings of the changes that are useful to
affect in our unusual applications, we might find ourselves making
arrays with adjustable components that we are able to "tune" by ear
for a particular setting. Rob D.
>John Hartog
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