Meeting microphones

[DALEWP1]

I'm merging two microphones into one helmet so I can have a wired connect to my airband radio and a Bluetooth connection. My plan is to just solder in the leads from the BT mic to the existing mic in my helmet. Do I need to add a diode so one mic didn't break feed to the other? Or is there something else I need to do to make it work correctly?

[Analog Kid]

Diode doesn't sound like a good idea at all.

Have you tried just putting them in parallel? That seems the most obvious solution. If they're both the same type (dynamic or electret) that should work.

If that doesn't work then you'll have to rig up some kind of preamp/mixer with an input stage for each mike.

[DALEWP1]

OK. I am basically a newb with all this, so I appreciate it.

So, to further my education, why would a diode not be a good idea?

[Analog Kid]

For one thing, it would clip have the signal, distorting it.
You don't need to "protect" the microphone from the other mike's signal; it's not going to damage it.

Can you temporarily wire them both in parallel and see how that works?

[themadhippy]

You don't need to "protect" the microphone from the other mike's signal; it's not going to damage it.

unless ones a ribbon mic and the other needs  48v phantom shoved up it,also paralleling 2 mics that require phantom maybe try and pull to much current from the phantom supply thats limited (or should be) to 10ma

[Analog Kid]

Where in the world do you get 48v. phantom power? The OP's talking about a bike helmet mike and some BlueTooth thing. No ribbon mikes here.

[CaptDon]

The one problem you may run into would be if one mic is a dynamic and doesn't want any voltage applied to it and the other mic is a FET/Condensor mic and needs a feeble supply voltage and current. That combination simply won't work and could damage the dynamic mic. You may be lucky and both mic input circuits are similar and one mic can indeed feed both devices. A diode blocks current flow in one direction so obviously it is a bad idea since audio is an alternating wave.

[DALEWP1]

Oh, sure. That makes sense. So, I can merge these two systems together at the mic and it'll stand a good chance at working. I'll give it a try and see what happens.

Thanks for the help and education.