Adding external input to megaphone? electronics orientated

I want to be able to add a MP3 player to a megaphone, the megaphone I am looking at is rated at about 25 watts and contains an external microphone, very similar to CB microphone. My thoughts is to add a 1/8" jack somewhere for stereo/mono operation.
This is obviously not for amplifying music, I was thinking more or of prerecorded vocals and I am willing to accept the minimal frequency range.

Where would a MP3 player tap in? same as the external Mic? Would over-modulation be an issue? I have not purchased the megaphone yet and was hoping for some insight first.

Thanks!
Pyd

Pydpiper said:

I want to be able to add a MP3 player to a megaphone...Where would a MP3 player tap in? same as the external Mic? Would over-modulation be an issue? I have not purchased the megaphone yet and was hoping for some insight first...Thanks!

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Not sure what you mean by "external microphone."

Do you mean the microphone is a separate unit that plugs into the megaphone? Or, do you just mean that the sound input area of the microphone is exposed on the outside of the megaphone?

Either way, matching an MP3 player to a megaphone is fairly trivial. You can probably get by with just adding a jack, although adding a jack and a couple of resistors might be better. A perfectionist might use an op-amp for impedance matching and peak limiting.


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I have the megaphone now, I also picked up a 1/8" jack to install.
I want to install the jack to this microphone;

is it as simple as jumping in at microphone level?
My intention is to be able to plug a MP3 player into it to amplify animal noises.
Will the plug I bought (5 pin stereo, I will bridge left and right) override the internal mic? The jack is laying inside the cover in photo.

I would guess the Mic is amped a bit and probably would cause sever distortion with an mp3 player in it's place. Definitely worth a try and keep the volume really low.

Pydpiper said:

...My intention is to be able to plug a MP3 player into it to amplify animal noises.

Click to expand...

Ohhhh, I was thinking psychological warfare at the "neighbor" level!

From the photograph, that microphone looks like an "electret condenser mic", and headphone-level output (such as that output by an MP3 player) would severely overload the input of that megaphone's audio amplifier.

You would probably need to have both impedance matching and input voltage level (peak) limiting to get even halfway decent sound (voice) out of the megaphone.