Originally posted by Ceremonsen Do you mean an external recorder like Zoom H4n, or Tascam DR40?
A stereo pair is a mic configuration, but yes, both the Zoom and the Tascam have two cardioid condenser microphones in a stereo pair arrangment (albeit in two different ways).
Microphone practice - Wikipedia, the free encyclopedia ORTF stereo technique - Wikipedia, the free encyclopedia NOS stereo technique - Wikipedia, the free encyclopedia
Only don't expect results comparable with those you can get even with, say, a matched pair of Rode NT5 and a Focusrite Scarlet 2i2: even though that is pretty low-end stuff, it's still better than a do-it-all, swiss-army-knife-type portable device.
It will, be, anyway, a massive improvement over in-camera audio, if only for the fact that you can record uncompressed WAV files at 44.1kHz 16bit (even at 96kHz and 24bit but, well, that's only marketing...) instead of the lossy AAC track of the video file.
Side note (mainly intended as a curiosity): some Android tablets/cellphones allow recording through an USB audio interface via OTG, so it is theoretically possible to attach an audio interface like the 2i2 to a tablet and record audio in real time without the need of a PC/Mac.
Just bear in mind that:
1. it's something I would call "experimental"
2. it's likely to drain the battery pretty fast, since you'll be powering the interface with the phone and probably supplying phantom power to the mics.
3. check carefully the capabilities of the SoC of the Android device you intend to use/purchase, since the ability to process and record audio in real time is not something manufacturers consider or advertise, so you'll probably want to check on the internet in places like these:
http://www.wildmountainechoes.com/equipment/audio-recording-with-a-smartphone/ http://www.extreamsd.com/USBAudioRecorderPRO/ (scroll down for a list of compatible devices)