What is automatic double tracking?

Automatic double tracking, or A.D.T. is the process where we copy a signal and make it sound like the singer or band member overdubbed the exact same thing over the original track. Like double tracking, but cheaper and easier.

Sometimes it's hard to make a singer phrase his vocals exactly the way he did before. It might take hours of overdubbing before you nail that perfect second take. But with automatic double tracking you can achieve similar result in a fraction of the time.

A.D.T. has been used on countless records in modern music history, most notably for vocals and guitar. John Lennon is famous for using A.D.T. in almost all of his later tracks. Being so insecure about his voice, he loved the sound the engineers got when they doubled it in this manner.

Another notable mention of A.D.T is the guitar solo in the track Money by Pink Floyd where Dave Gilmour uses automatic double tracking to enhance his guitar playing so effectively.

How do you achieve this effect?

We create this effect by doubling the track and playing it back a few milliseconds behind the original track, creating this pseudo doubled line that thickens up the track and gives it more punch. There are a few ways you can do this. You can either copy the track directly and move it manually until it is only a fraction of a second behind the other waveform.

adt manual

Notice that the waveforms don't match

delay send You also send your track via an aux to a bus where you insert a delay plugin that takes care of delaying the track for you. This is an easier and more effective way since you have greater control with using the delay instead of doing it all manually.

Now, we can pan these tracks to give it a wider stereo image, which is often done.

Here is an example of widening the vocals with A.D.T. Listen to the dry sound in the center first

Now I've doubled it by using a delayed send of about 23 milliseconds. I've panned the main vocal around 30 to the left and the delayed double track is 30 to the left. Notice the wider sound.

Doubling guitars

In this example I'm panning two guitar riffs, delayed 25ms hard left and hard right. The first example is the dry riff in the center.

Now let's hear it when the guitar is doubled with delay and panned hard left and hard right.

If you are sick of playing the same riff over and over again, this is a good way to take that extra work off your shoulders. And by panning them hard left and right you free up the center for all the lead stuff like vocals and solos.