Double tracking have been used in music for many decades, simply because it is a great way to make the final sound more dense, rich and powerful.
The 2 most common types of sounds to do double tracking on are: Vocals and Rhythm Guitar. But you can use it for any type of instrument.
For example, if you record a full section of violins or any other type of instruments, you automatically get the effect of double tracking in that recording.
The reason is that when you record another layer of the same instrument playing the same part, you get all the tiny variations of pitch, timing, tone color, character etc.
How to do Double Tracking
- Record the Main Part until you get a Great Take
- Clean up the Main Part for Optimal Timing & Pitch
- Record as many layers you want playing the same part
- Edit the double-tracked layers for timing and pitch consistency
- Mix the Main Part in Front and Centre
- Mix the Double Tracked Parts Back and to the Sides
- Group all Parts together and Glue with Compression etc.