If you don't like reading, just watch the video.
Ok, so you do like reading. Fine. I'll keep typing then.
What is the proximity effect?
The proximity effect (sometimes called the bass proximity effect) occurs when you move a microphone closer to the sound source. The sound source in voice over is pretty obvious. It's you. The voice. The closer you are to the mic, the more low end it picks up.
Lower frequencies appear quieter because the human ear is less sensitive at that end of the spectrum (also the high end but we're not talking about dog whistles today). So it would make sense then, that if you move a low frequency closer to a mic, you'll hear it more clearly.
Why would I want to do that though?
There's many applications for a deeper sounding, rich, smooth, warm tone of voice. Think about those adverts about melting chocolate, guided meditations or voicemails at the spa.
It's also a good tool to have in your repertoire. You never know when someone might send you a script for a commercial about being on a beach, while eating M&S food and getting a massage. Perfect.
Ok, so how do I do it?
It's in the video.
But you could do more reading if you like...
Get in as close to the microphone as you can without touching the pop shield/mic.
Turn side on. Not at a total right angle, but getting there.
Lower the projection of your voice (talk quieter). Not a whisper, but softly.
If you can, lower the pitch of your voice. If you can't, you'll still have a nice tone.
That's it. Simple. It's really fun to play with and opens up new possibilities you might not have known existed. Don't worry if you don't have a naturally deep voice, this will still have a nice effect for you.