#### Willen

##### Well-Known Member
Hi,
These type of 25mm condenser capsule has been rated around $4 in some sites. Cheapest 34mm capsules costs more than$20 in same site. So comparatively the 25mm sounds pretty cheap. I am just curious about its internal structure. Are they true condenser capsule which needs 48V phantom power? Or are they electret capsule which has FET inside?

If anyone have used already then I would be curious to read about its performance? (If really it has 25mm or little bit less diameter diaphragm then I hope it should perform well.)

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#### rjenkinsgb

##### Well-Known Member
Hi Willen,

I've seen those online & just looked at a few listings again, but nothing makes it 100% clear what they are.
They could be electret without a built-in preamp, or they could be condenser.

The only way to know is try one without bias voltage to start with and see if it gives any output?

#### audioguru

##### Well-Known Member
Why would a company make those things without spec's and applications for them?

#### Willen

##### Well-Known Member
Why would a company make those things without spec's and applications for them?
I think these are Chinese and they manufacture no spec parts and sell to another manufacturer. The 2nd manufacturer just labels it and sell with brand name and spec.

I tested small electret capsule and they sounds pretty nice high frequency but poor with low. So I guess the 25mm capsule should work nice with low frequency, because of its large diaphragm.

#### audioguru

##### Well-Known Member
Most electret mic capsules are about 6mm in diameter and have a very flat frequency response from about 20Hz or lower to 20KHz or higher like this one:

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#### Willen

##### Well-Known Member
Most electret mic capsules are about 6mm in diameter and have a very flat frequency response from about 20Hz or lower to 20KHz or higher like this one:
If the capsule has no internal FET then one can use very low noise FET like 2SK118 and can achieve nice quality audio. Wow!

#### rjenkinsgb

##### Well-Known Member
Hi Willen,
yes, I would be very interested to know how well they work, at that price!

AG - That Panasonic capsule is incredibly good, though they seem to be discontinued.
Small electret capsules with a genuinely good frequency response are relatively scarce, most have either poor low end, poor high end, or both.

A lot of mics sold as "Condenser" (with the implication that they are true condenser rather than electret) are scams, usually with tiny electret capsules.
Even some big-name ones are electret, though they avoid using that word!

eg. AT2020 "Studio condenser" microphone - from the specs:
"ELEMENT Fixed-charge back plate, permanently polarized condenser"
An electret, in other words..

Traditional "Studio condenser" class mics have capsules such as this:

#### audioguru

##### Well-Known Member
I think that all electret mics use a low noise Jfet in them.

The third electret mic at Digikey is from CUI and its datasheet says 20Hz to 20kHz and shows a flat response from 20Hz to about 7.2kHz then a +4dB increase at about 16kHz. Its output at 20kHz is down about 1.5dB. It costs only \$1.28US.

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