I recently received an email from someone asking me how I got the voice recording in my videos to sound so clear and strong. The answer to that question is much more complex than I'll deal with here, but that person asked me mostly about the microphone I used, and if that could make a big difference in getting better recordings. Here's what I replied:

I currently use an EV RE320 in a shock mount.

I have it plugged into a Behringer U-Phoria audio interface, and I've actually modified my setup recently. I used to use a Cathedral Pipes Durham pre-amp, but I have since switched to using a full 'Voice Processor' from Symetrix (the 528E), which is most often used for podcasting or radio studio settings.

Anyways, the main thing you have to keep in mind is that microphones pick up the sound in the environment, and there are three ways to combat the problem of 'picking up sound in the environment' vs. 'picking up your voice':

1. Get the source of the sound (your mouth) closer to the microphone (so it is louder than other background sounds, reducing the 'signal to noise' ratio and making it so you don't have to boost your microphone signal so much you hear background noises). There's a reason podcasters and radio personalities have the mic on a boom arm—so they can get it close!
2. Get your room as quiet as possible (there are ways to do this cheap, and there are ways you can do it really well/expensive)—that's not always that practical though.
3. Make sure you use a 'directional' mic. The RE320 is designed for voice, and has a 'cardioid' pattern that picks up more sound in front of the mic than the back. Some mics (like shotgun microphones) have 'supercardioid' that is even more targeted and that's why they use those on movie sets and TV where the mic is further from those speaking.

I'll probably end up doing a video on my current studio setup soon.