Q:

Doubling a track

I was reading an article about recording a guitar and the guy was recommending doubling the track by actually recording it twice. I realize that this thickens up the sound which is good but is playing it a second time any different then just duplicating the recorded tracks in my DAW? It still beefs up the sound but I'm not forced to play it perfectly 2 times. ThoughtS?

A:

Actually recording it twice produces a "chorus" effect.  Think of the vocals in your average Queen song; Freddie Mercury would often sing the same thing multiple times with the same approximate timing and pitch, but due to natural imperfections it sounds almost as if he's singing with someone else.  Simply doubling the same track won't do this, even if you offset it a little; you're trying to introduce imperfection, and a perfect copy won't do that.
This is different from recording the second part with a different guitar, of course.

A:

There are many reasons to double guitars in a recording, but the main one, in my opinion is because you want to pan the two tracks on the side during mix. Guitars have frequencies that typically compete with the voice tracks, which you want to keep in the middle.
Now, simply doubling a track won't cut it, because there is no way you can move the two tracks on the left and the right (it would always appear in the center of the spectrum).
There are alternatives to dubbing guitars - none of them give the same effect in my opinion but you might want to try them.

use a chorus/phaser/flanger/pitch shifter: this gives you another track which you can pan.
use a short delay between two copies: this gives though has an aftereffect due to phases known as the "comb effect" which is probably not very desirable.

If instead you opt for dubbing them you have the following options:

Use the same setup and play them as close as possible. This is the classic "wall of sound" choice (actually it's not that uncommon to use four guitars).
Use different setups and play them as close as possible. This can sound very nice but it's tricky to get balanced right in the mix. A classic combo is using a strat and a les paul.
Use the same setup but play different parts. For example, on strumming parts, it's great if the strumming rhythms are different.
Use different setups and different parts: classically, a strumming six string and a strumming twelve strings.

A:

If you literally duplicate it in your DAW, then you have a sample-for-sample copy of the original track.  Unless you change one of the recordings somehow, it won't make the resultant sound beefier so much as it will make it twice the volume.
Re-recording it causes a different-enough sound that it allows things to be "thicker" because even though it is one part, it sounds like there are two instruments playing it.  Because there are.
If you don't want to play it a second time for whatever reason (and there can be many reasons for this) you might consider messing with the other track a bit.  Delay it slightly, vary the pitch in tiny increments over time, things like that.  Alternately, you can omit the second track entirely, and just put a delay or chorus effect on the original track.  A chorus is designed to produce an effect very similar to what you described.

