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Electret with inside battery

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Electronman

New Member
Hello,

today I found a electeret mic that use a AA 1.5V battey inside.
Are they designed to work with dynamic inputs like instead of a dynamic mic?
I guess so because the comapny has biased the electret mic by a battery, That means the input does not need a biasing resistor for the electer mic so I thought maybe these mics are for dynamic inputs??
 

Sceadwian

Banned
Not necessarily dynamic, just any input that doesn't have the bias voltage built into it. Basically means you can plug it into a line-in jack instead of a mic in.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Not necessarily dynamic, just any input that doesn't have the bias voltage built into it. Basically means you can plug it into a line-in jack instead of a mic in.
No, not the line-in, it's a mike level signal, not a line one.

It's so you can simply plug it directly in the mike input of a mixer or amplifier, as the OP says it essentially makes it like a dynamic mike.
 

Sceadwian

Banned
What's the typical peak to peak those electret modules put out after the integral amp?
 

audioguru

Well-Known Member
Most Helpful Member
An electret mic does not have "an intergral amplifier" inside. It is just a Jfet impedance converter that converts the giga-ohms of the condenser to a few k-ohms with a gain of maybe only 3.
The output level is 5mV to 15mV RMS, the same as a dynamic mic.
 

Sceadwian

Banned
That would be my definition of an integral amplifier audioguru. It converts both impedance and provides some gain.. What else would you call it?
 
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Nigel Goodwin

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Most Helpful Member
That would be my definition of an integral amplifier audioguru. It converts both impedance and provides some gain.. What else would you call it?
Very small one though, mostly it's for impedance matching - the gain is mainly a byproduct.

Basically you treat such a mike just as you would a dynamic one, and I've used them various times over the years - pretty decent for miking drums or guitar amps.
 

Electronman

New Member
Very small one though, mostly it's for impedance matching - the gain is mainly a byproduct.

Basically you treat such a mike just as you would a dynamic one, and I've used them various times over the years - pretty decent for miking drums or guitar amps.
Are they good for higher frequencies than dynamic one?
I hardly could find this electeret mic with a battery inside, I Do not know the reason but that caused me to think which one is better for performance and or for recording?
Besides I tried both my dynamic and electeret battery powered mic with a homemade amplifier, both did work but the output was several times than the dynamic one.

What's the story of an 'integral amplifier ' really?
 

Sceadwian

Banned
Even impedance adjustment is still current amplification though. Sorry, I'm being anal.

Basically an electret mic by itself can not provide enough of a current or voltage (both really) to drive a line or even a mic input. It needs a DC bias (the battery provides that) and a few bias resistors (probably built into your battery mic) to amplify the signal to the point where it's useable. All modern electrets have a jfet built into them which provides this amplification. Typically the MIC input of a PC and I'm sure many other mic input jacks will also carry this bias voltage for electret mics. Generally running a dynamic mic on a mic in jack designed for an electet mic will screw it up because it will apply the DC bias to the coil which wil highly affect it's clipping responce.
 
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audioguru

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Most dynamic mics do not have a flat frequency response because they have resonances. Electret mics usually have a very flat frequency response.

The FET inside an electret mic that is powered from only 1.5V overloads easily.
Dynamic mics work well inside a very loud drum and when a singer is screaming.
 

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Sceadwian

Banned
I think you're the one that mentioned it to me AG, but they also have high noise floors and low dynamic response. But on the plus side they can also be used to measure absolute air pressure.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Are they good for higher frequencies than dynamic one?
Different mikes are better for different purposes, electret mikes are generally good for recording purposes, as they have wide flat responses. They aren't very good as vocal mikes though.

I hardly could find this electeret mic with a battery inside, I Do not know the reason but that caused me to think which one is better for performance and or for recording?
For vocals, use dynamic mikes, for miking 'some' parts of the drums use condenser mikes, which is a more modern higher quality mike related to an electret.

Electret mikes have pretty well disappeared these days, almost everything in professional audio provides phantom power for condenser mikes.

There's no 'best' mike, you need a range of them, for different purposes - but don't be scared to try 'what you have' - the wrong mike is better than no mike :D

Besides I tried both my dynamic and electeret battery powered mic with a homemade amplifier, both did work but the output was several times than the dynamic one.

What's the story of an 'integral amplifier ' really?
It's to match the electret element, without it the mike wouldn't be useable, as it's FAR too high an impedance.
 

Mikebits

Well-Known Member
These Mic questions come up so frequently. Someone should write a MIC sticky.
 

audioguru

Well-Known Member
Most Helpful Member
I simply "stick" an electret mic to a preamp circuit that powers it. Simple.
Questions about a mic are "why does it produce a loud hum in my sound system?" or "why does it make a howling sound?".
 
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