Need help designing a couple of circuits to modify a voice changer

[revwolf]

Need Help Designing a couple of circuits to modify a voice changer.
i have a voice changer that is quiet(No volume control) so i would like to make it louder and give it a volume control. also i would like to add a powered microphone to it so it picks up my voice better. and i would like both circuits to be powered by batteries. i have a cheap stereo microphone i got off ebay(dont know what kind), i have and old small pair of 0.25W 8ohms (EA) connected stereo speakers, i would like to use for this and of course the voice changer.

 

[audioguru]

You didn't post the schematic of the voice changer so we do not know how to modify it.

What is a "powered" microphone? Is it an electret mic powered from a battery? We do not know anything about your cheap stereo mic and do not know if your voice changer circuit can use it.

You can make an LM386 power amplifier to make the voice louder until it causes howling feedback. A volume control is usually used with it.

Your speakers are very low power so maybe they are tiny. Then they will not work well.

 

[revwolf]

Ok sorry about not posting a schematic for a storebought voice changer. here are some bad pictures i took. sorry for the bad images, im not good with taking pics of small objects. it apears to be a multi layered PCB so i cant give a schematic of the circuit. the microphone i wish to add and make more sensative but clear has this information,
Microphone dimensions: 9mm x 7mm.
Sensitivity: -52dB ± 5dB.
Frequency range: 100 - 16KHZ.
Directivity: omnidirectional.
Impedance: =2.2kO.
Current consumption: 500µA.
Standard voltage: 4.5V.
Input plug diameter: 3.5mm.
Cable length: 1.5m.

 

[audioguru]

We do not know if the voice changer module uses a dynamic microphone that has a coil and a magnet like a little loudspeaker and generates a voltage, or if it uses and powers an electret microphone. Your photo shows an electret microphone. Did the voice changer module come with it?

The spec's you provided are for an electret microphone, probably it will sound exactly like the one in your photo.
Most electret microphones have the same sensitivity and clarity. It will be louder and maybe sound clearer (if the circuit is not overloaded by it) if it is closer to your mouth when you talk.

I was at a meeting tonight and the PA system was absolutely useless. The room was an echo chamber and the mic was much too far away from the people who mumbled at it. A person turned up the volume but it simply caused acoustical feedback howling without making the mumbling any louder. Two loudspeakers were far apart which made the echoes sound worse.

 

[revwolf]

The mic in the photo came with the voice changer. for it to work i need to have it just about in my mouth. thats why i want a circuit that will improve the mic so it does not have to be in my mouth to work.

 

[audioguru]

If we had the schematic then we can simply change the value of the gain-setting resistor in the mic preamp to give you any amount of sensitivity that you want.

You can add another mic preamp with adjustable gain between the mic and the existing mic preamp to increase the sensitivity.

If you increase the sensitivity of the mic so that it can hear the loudspeaker then the circuit will probably produce acoustical feedback howling.