I have not worked with the Studio1 adapter. I normally see the BeachTeks being used. I have used a BeachTek DXA-6 for years. I also have a juicedLink CX-231 and really like the audio it gets (big preamps). If your mics require power, then you either need to put a battery in the mic or the XLR adapter needs to provide "phantom power". Not all mics (even those that use a battery) can use phantom power, so be careful and be sure the mic can do that.
Both companies make an XLR adapter with LEDs showing audio level - but they are more expensive. If the camcorder goes into manual audio mode, there will be an audio meter or pair of meters on the view screen or LCD panel. Put the camcorder audio at about 1/2, then control the the rest of the audio from the gain controls on the XLR adapter.
The DXA-6 has a stereo/mono switch to center the audio. CX-231 has a switch to pan each channel Left/Center/Right. You can use these whether you use or or two mics - very handy.
Download and read through the camcorder manuals to understand what sort of manual audio controls they have - if any... Just because a camcorder has the mic jack does not mean it has manual audio control... Assuming can result in unexpected feature availability.
I'm looking into getting a Canon HF11 but i want better sound quality. It has a 1/8" mic input, so could I get a simple xlr to 1/8" converter? but if the input doesn't provide power, do i have to get something different? i was looking at the Studio 1 adapter and it seems good, but i want to be able to see the mics levels. Would the camera pick up levels from mic input? Also, how does the output work? if i have one mic recording stereo, does the adapter output the combined channels?
the HG 21 has the same mic input so i figured if someone knew about the HG21 it would apply to the HF11