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One of the joys of choosing the Schoeps mics was that they enabled me to change
capsules with different polar diaphragms. I could therefore try different recording
techniques.
Generally, mics are divided into two separate types, pressure operated and pressure
gradient. Pressure-operated mics are omni directional. They usually have the flattest
response and an extended top end. Pressure-gradient mics are usually
more directional, cardioid etc. Their low-frequency response falls off more rapidly
than an omni-directional mic and most of them have a little bump at the top end.
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I decided therefore that the technique for Venice would be based on a pair
of omni-directional mics for the flattest frequency response. To improve the stereo
imaging, I would use a Jecklin disc between the mics. That is an
acoustically opaque disc about 30 centimeters in diameter. When placed between the mics, it separates them at high frequencies due to size and improves stereo
imaging but has no effect at lower frequencies. The gentleman who invented it at
one time worked as chief engineer for Swiss radio.
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The system I was going to use was the latest implementation, with the disc 35cm in diameter and the mics 36cm apart. I did some tests where
Françoise was talking at the left, center and right positions. Listening before and after
adding the disc revealed how much the imaging improved. Making the disc was fun.
I used some heavy-duty foam, a piece of Perspex and some fake lamb’s wool.
The last piece of equipment I needed was a microphone stand. I would need
something to hold the mics up to 4 meters off the ground. After some lateral thinking, I came
up with a lighting stand made by the Italian company Manfrotto. Their stands
have been used on many feature films and are superbly built.
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Now came time to gather our forces and set off to Venice. I would have no time to
take photographs and decided to ask a young photography student,
Francesca Lever, to capture the event. As well as Françoise
who speaks fluent Italian, I asked my friend George Thomsen of Prometheus
Audio to come and help carry all the gear. With everything in place, we were off.
Upon arrival, the orchestra agreed that I could set up the equipment two hours
prior to the public performance to check the positioning of the mic rig and
assess sound levels. This meant that we had the afternoon off to look around
Venice. It really is an amazing city. If you have not already done so, you should
visit before sea levels continue to rise.
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Then came time to set up the equipment. How often do reviewers say that by
moving the loudspeaker just a few inches, the sound can completely change? It is the same for a pair of mics. Too close to the instruments and you can lose the sense
of the acoustic space. Too far away in the ambient field and the instruments will
sound as through they were swimming around.
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I found that the mics were best placed on the
center line about half a meter in front of the podium and about three meters above the
church floor. Even though the mics were omni-directional, they still retain a slight
directionality so I pointed them down approximately 30°.
The cables were also made by Schoeps. Those were ten meters long and picked for their quality construction. I actually put them on my
Nordost cable burner to wake them up for a week as the output of the mics
themselves is very low. The Nagra was set to record Bwav files at 24-bit/192kHz
and with my Sennheiser headphones plugged in, we were ready to begin. No limiter
was used, no compression and no equalization.
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