How to Fatten a Sound in a Mix

I was doing mixing lately on my upcoming album. So I actually did some research on mixing a song. Sometimes when I hear a sound so thin that I really want to fatten it up (sometimes referred as ‘phat’ sound). It was taught in mixing using the visual imaging method. The secret is quite simple: use a delay shorter than 30 milliseconds. Why 30 milliseconds (0.03 second)? Scientific research shows that delay shorter than 30 milliseconds can’t be perceived by the human hearing. There are several tricks you can ‘phatten’ or fatten a sound using this simple concept.
Use delay effects
Insert a delay effect into the track you wish to fatten. Pan the original dry track to the left or right, and pan the effect output to the opposite side. How fat you want it to be? You can control the fatness by setting the width of your pan. But, made sure it is less than 30 millisecond delay You can also try it with more than that. I am sure you are able to hear the difference between fat and echo.
Duplicate the original track and move the copied track
Without delay effect? Don’t worry, you still can create the delay manually. Just copy the exact track you intend to fatten. So now you have two exactly same tracks. Move the copied track a bit behind in your sequence. Check that it is delayed by 30 milliseconds. Pan the two tracks in opposite direction. The result is still a fatten sound.
Duplicate with a similar patch
This is what I normally do. I search for another patch which is 50-80% similar to the original. For example, if I want to fatten a synth lead, I will find another similar synth lead from a different sample or synthesizer. Copy the midi track and send them to two different outputs. I will move the MIDI track by 5-30 milliseconds behind and hard pan both the track to different direction. End up a ‘phat’ synth lead!