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Old 31st October 2012, 05:17 PM   #28721
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Richard makes sense. It should be realized by everyone that mike design has been going on for a very long time, people have seriously tried to overcome limitations in virtually every type of mike concept, and that there are ALWAYS TRADEOFFS.
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Old 31st October 2012, 05:26 PM   #28722
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It is by definition: design means optimization.
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Old 31st October 2012, 06:50 PM   #28723
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Quote:
Originally Posted by john curl View Post
people have seriously tried to overcome limitations in virtually every type of mike concept, and that there are ALWAYS TRADEOFFS.
It is good to be reminded that the thermal noise of the air pressure on the diaphragm limits the noise at mid-high frequencies and the RF techniques are lower noise mainly at the low end because they don't need the G-Ohm bias resistor. There is a trade off in terms of reliabiliy and JFET leakage that makes a commercial designer think twice about simply dropping in a 50G Ohm resistor.
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Old 31st October 2012, 06:59 PM   #28724
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If we speak about condenser microphone, there is an optimal diaphragm size, as a compromise between noise level and upper frequency response. Neuman microphones were successful because they found this optimum for frequency response that was standard then. No need for 50G resistors, and even 0.5G resistors are shunted well by about 100 pF of the capsule capacitance.
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Last edited by Wavebourn; 31st October 2012 at 07:03 PM.
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Old 31st October 2012, 07:02 PM   #28725
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There is a trade off in terms of reliabiliy and JFET leakage that makes a commercial designer think twice about simply dropping in a 50G Ohm resistor.
Yes, and best IGBTs have a lower noise factor than FETs.
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Old 31st October 2012, 07:04 PM   #28726
bcarso is offline bcarso  United States
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Yes, and best IGBTs have a lower noise factor than FETs.
Please give us an example!
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Old 31st October 2012, 07:38 PM   #28727
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Please give us an example!
Probably he means less interference from light dimmers with IGBT than from light dimmers with FETS?
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Old 31st October 2012, 07:57 PM   #28728
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Originally Posted by Wavebourn View Post
If we speak about condenser microphone, there is an optimal diaphragm size, as a compromise between noise level and upper frequency response. Neuman microphones were successful because they found this optimum for frequency response that was standard then. No need for 50G resistors, and even 0.5G resistors are shunted well by about 100 pF of the capsule capacitance.
Still a few dB of room for improvment at those numbers, but yes at 1" it works. They still had to work hard to get the frequency response.
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Old 31st October 2012, 08:06 PM   #28729
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Santa,
I want a 1/4" B&K microphone for Xmas for testing your speakers for the North Pole. And you can include the power supply that goes with it. I don't care how old it is as long as it works. Would help me with my beryllium dome tweeter development, my Earthworks mike won't go that high.

ps. I have tried to be a good boy this year and keep out of trouble. Thanks for bringing down the price of neodymium magnets this year.
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Old 31st October 2012, 08:18 PM   #28730
dimitri is offline dimitri  United States
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1/4" B&K microphone, preamp and battery powered power supply will be around $1K on fleabay
or you can replace preamp and battery powered power supply with 4048 ACO Pacific phantom powered preamp(body)
I can lend you 1/4" B&K microphone.

Last edited by dimitri; 31st October 2012 at 08:23 PM.
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