Greetings!

I am new to the audio game.

My work recently purchased a Canon Vixia HG21 camcorder, which has a 3.5mm audio input. We have some old microphones with an XLR connection lying around, and I found an XLR to 3.5mm adapter.

Upon plugging the mic into the adapter, and the adapter into the camcorder, I did some tests. While the audio meter on the camera shows that it's picking up the sound coming from the microphone, all I hear on the playback is an annoying, high pitched sqeaking sound. It actually sounds similar to thousands of crickets making noise at the same time.

Does anybody know what the problem is with my setup, and what I can do to fix it?

Thanks!!

Several questions, first what's the exact model of microphone? That will determine what kind of power if any is required by the mic.
Second you may need to test how your adapter is wired. If it isn't wired correctly to convert a balanced XLR into stereo unbalanced 1/8-inch TRS, it won't work.
Third, if you're listening to the camera playback and there's only one jack that serves as both headphone out or A/V Line out, it must be set correctly in the menu for the correct sound. It also has to be set correctly for both record monitoring and playback separately.
Last the mic jack may have "Plug-In Power" on it but most Canon's are pretty good about either not having it or being able to shut it off when it isn't needed.

Where do you work? If it's for an AV company, chances are the thing is wired incorrectly. In this industry most XLR to 1/8"TRS is for running wired remotes over long distances for projectors and such.

Here is me doing my best to answer the questions asked:

I tried this with two separate microphones. The microphones are an Audio-Technica PRO4L (undirectional) and a PERCO PM4000A.

I wouldn't have any idea how to test the wiring of the adapter. It's one I found in our old box of audio goodies. Not sure where it's from or when it was made.

The audio playback on the camcorder that I have been using is the external speaker that is built into the camcorder itself. No connections to anything.

I work for a health region, not an AV company. Chances are, based on the sound of things, the adapter is wired incorrectly. Is there anywhere that anybody can suggest that I could purchase an XLR to 1/8" adapter that would work for this small budget setup?

Thanks for the feedback!

Here you are good sir.

Pearstone | LMT100 - Low to High Impedance Matching | 8111240 (http://www.bhphotovideo.com/c/product/589872-REG/Pearstone_8111240_LMT100_Low_to.html)