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Gear / Technical Help => Microphones & Setup => Topic started by: Roving Sign on October 26, 2007, 08:43:42 PM
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Is there any difference...? Seems like the older mics all call it a "Back Electret"
I've read somewhere that the "back" variety are more prone to loss of charge...? Any truth?
Wiki also mentions a "Front electret" - assuming this is the same as just saying "electret"
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Is there any difference...? Seems like the older mics all call it a "Back Electret"
I've read somewhere that the "back" variety are more prone to loss of charge...? Any truth?
Wiki also mentions a "Front electret" - assuming this is the same as just saying "electret"
The first electrets had the charge on the diaphragm. But this limited materials and lost charge. Any modern electret is a "back electret", so people take out the word "back" now.
One thing I worry about is mics losing charge over time. I'm thinking of the really old electrets, like AKG Ck1x and some of the older omni mics. I don't know if this happens or not, though.
Richard
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The original electrets were "front" electrets, with the electret material on the diaphragm. The diaphragm was a bit stiff and unresponsive, but they were cheap to make. The only front electrets nowadays (as far as I know) are in telephones and dictaphones.
The back-electret moves the electret material to the back-plate, making the diaphragm the same as a true condenser and a lot mote responsive. Originally invented by Sennheiser, the patents expired ages ago (so I understand) and any good electret nowadays will be a back-electret (often called a pre-polarized condenser).
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..... I'm thinking of the really old electrets, like AKG Ck1x and some of the older omni mics.
The old AKG CK1 was *not* an electret - it was a standard AF condenser.
The new C414 *is* an electret, though.
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John, I think you probably mean that AKG's C 451 B "reissue" is an electret, while the original C 451s and 452s were not. The C 414-series microphones are still polarized in the traditional manner with externally applied DC; their pattern-switching arrangement depends on that.
Do you have any evidence for the claim that Sennheiser invented the back electret? I'd like to check that out, since I remember differently.
--best regards
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JLI Electroncs sells the TranSound line of electrets, some with good looking specs with a range of both back electrets and electrets. Some models availabe with a choice between the two types. Why would they offer the choice or even offer front electrets if it was as simple as " newer tech " elimanating front electrets as quality capsules?
Unfortunately, I think JLI changed web site design, losing some spec. l istings in the process.
I'm glad this question got asked, really curious about this......
Joe
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You can usually tell the 'back' electrets from the 'front' capsules from the extended >20K Hz high frequency response of the 'back' types. Front types usually top out at <16K Hz
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John, I think you probably mean that AKG's C 451 B "reissue" is an electret, while the original C 451s and 452s were not. The C 414-series microphones are still polarized in the traditional manner with externally applied DC; their pattern-switching arrangement depends on that.
Yes, you are correct - I was writing quickly and put 414 instead of 451.
Do you have any evidence for the claim that Sennheiser invented the back electret? I'd like to check that out, since I remember differently.
Only this is what someone high up at Sennheiser told me many years ago.
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..... I'm thinking of the really old electrets, like AKG Ck1x and some of the older omni mics.
The old AKG CK1 was *not* an electret - it was a standard AF condenser.
The new C414 *is* an electret, though.
Richard is referring to the active capsules AKG made for use with the mk46 cables, CK1X, CK2X, CK3X. These *are* electrets, although the standard CK capsules are not.