Quote:
Originally Posted by
flintyplus 
XLR inputs are something i have never had on a camcorder,i have several external mics most with 3.5 plugs and 1 with a 2.5 plug,is there any way ordinary 3.5 mics can be plugged into XLR inputs and be powered by the cam,that is one thing XLR does as far as i know plus use expensive pro mics,none of the usual rode sennheiser range seem to be XLR.
Many XLR condensor microphones need to be powered with what is known as phantom voltage, usually listed as 48V, which is carried by the XLR cable connecting to the microphone. The 48V would usually be provided by a mixer or a pro camcorder to which the other end of the cable would be attached. Some XLR condensor microphones can alternately be powered by an internal battery (usually 1.5 V AA battery with some internal circuitry), and therefore can be used with equipment that does not provide phantom power. For example, one could use an impedance matching XLR to 3.5 mm cable to connect such a battery powered condensor microphone to the 3.5 mm jack on a consumer camcorder or consumer portable digital audio recorder, both of which typically do not provide 48V phantom power. If you have such a microphone, and have the option of using internal battery power or 48V phantom power, 48V phantom power would be the best choice. Some XLR microphones are dynamic microphones, which do not need phantom or battery power.
Do not confuse phantom power provided by professional equipment with plug in power or bias voltage (often 1.5V to 3V) that is often provided on the 3.5 mm mic input jack on consumer camcorders or consumer digital audio recorders. The plug in power or bias voltage will NOT power professional XLR condensor microphones that need phantom power. It will power some consumer level microphones that need power.
The reason to use XLR is that there are a huge variety of XLR microphones available at all quality levels including top professional level microphones. In addition, higher quality equipment uses XLR connectors to connect microphones, and XLR cables provide excellent immunity to noise on long cable runs, due to their balanced electrical construction. Consumer level cables using 3.5 mm plugs and jacks could potentially pick up electrical noise.
It is certainly possible to get a consumer microphone with a 3.5 mm plug to connect to XLR, using the appropriate adapter cable with impedance matching, but in general most people don't want to do that. Why hook up a consumer level microphone to expensive professional mixers and camcorders with XLR? The more likely scenario is hooking up a high quality XLR microphone to a consumer camcorder or digital audio recorder that has a 3.5 mm mic input.
Having said all of that, it is certainly possible to get OK sound quality using the appropriate consumer level equipment - just don't expect the level of audio quality found in most feature films or scripted TV shows.
