Well for starters, not all microphones are compatible with iPods, so if you're not using a compatible one, the iPod will think it's a pair of headphones, so you will neither hear nor record anything. Furthermore. When you plug an external microphone into an iPod, it disables the speakers. The purpose of the external microphone is simply for calls (on an iPhone) or recordings. The reason it disables the speakers is because of the risk of feedback. See, feedback is caused by the audio source, feeding back into itself. Basically, when the microphone picks up what the speakers are outputting. This isn't a risk with the built in microphone because of all the extensive testing and precise designing, but when you plug an external microphone in, it could go in front of the speakers and cause feedback. Any questions?
