At 5:16 AM +0000 1/17/08, John Hartog wrote:
>Hi Rob,
>I will try to address some of your comments as I prepare dinner.
>[now opening a bag of potato chips, and pouring some beer]
>
>> I've always admired the way dishes can isolate details-- getting more
>> stereo "liveliness" would be a great plus.
>>
>> Just to be sure, your dish is divided in half vertically, correct?
>
>Yes vertically.
>[chomping chips and beer while chopping a large beet into slices]
>
>> It sounds like the highway(?) is on the left in the recording. Is
>> that that correct orientation, field-wise? I noticed the right
>> channel of the sound file is showing more resonance between 250-500
>> Hz than the left and I was trying to explain this flip.
>>
>><http://ad2004.hku.nl/naturesound/RobD/Hartog-SB-Left-Right-Channels.jpg>http://ad2004.hku.nl/naturesound/RobD/Hartog-SB-Left-Right-Channels.jpg
>> The gain is also lower on the right channel so the difference in
>> resonance is probably more pronounced than this.
>
>Thank you for analyzing the recording.
>The wetland is completely surrounded by highway noise, and train
>noise, though most of the roar emanates from the rear and left of the
>microphones. It would be hard to say where the resonance you see is
>coming from.
Perhaps from the dish cavity itself. A little dampening of the
surfaces of the center divider might eliminate it.
>Solving the flip-flop problem was my fundamental reason for
>experimenting with a large barrier that extends beyond the dish. The
>LP barrier seemed to work well for eliminating flip flop. This one,
>for some adjustability for mic position in both directions, behind and
>forward of true focus, meant leaving more space behind the barrier. I
>seem to notice some flip flop bleeding through as the gap increases.
I see that the side or off-axis sound is mostly direct (not mostly
reflected as I first thought). This may be part of why you're getting
better results with the capsules pointed more towards the lip/edge of
the dish. Since your divider extends beyond the lip of the dish,
that might be a good location to try additional capsules in parallel
with the focal point capsules. The front ones could be directed ~ 115
degrees. Tom Robinson's battery supply, based on Richard's schematic,
would probably work on a pair of the 183's:
http://ad2004.hku.nl/naturesound/RobD/TripletsParallelPoweringSchematic.jpg
Yes, a 4 channel Samson H2 could be another excellent way to address
the challenge. I'll need to follow through on getting one for
testing. Rob D.
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