Recording Vocals

ADT, or Automated Double Tracking

The Beatles laid down some great vocal performances. They were well sung & well recorded. They had a certain fullness to them, and that’s because they were (for the most part) Double Tracked. Initially, they recorded a second vocal track to go along with the lead track. Later in their career, Lennon wanted to shorten the process.

Ken Townshend, a recording engineer at Abbey Road, came up with Automatic Double Tracking (ADT)  in 1966. ADT involves making a copy of the original vocal pass on another tape recorder (the second track’s playback speed is altered to create the effect). Both recordings are then blended and mixed back into the final recording to fatten up the sound.

Up until last year 2008 home-based musicians were forced to create the effect using digital delay, and manually time/pitch shifting a second vocal track. Thanks to the fine programming efforts of Vacuumsound you can get your vocals sounding great in no time at all. Here’s what they say about their own plug:

The ADT Plug-In takes a mono input signal and creates a stereo output. The original input signal will be output on one channel, the new ADT signal on the other. Blending the two is also possible. The Plug-In allows to control the delay time (10 – 50ms), Wow and Flutter (both with intensity in % and frequency). All values are based on the technical data of the tape machines that was originally used to create this effect.

The GUI is nothing fancy, but everything works as it should, and the results are fantastic. The ADT plug also sounds great on electric guitars.

I found a post yesterday by another musician-blogger curious about The Beatles’ use of ADT.  He  imported the songs into Pro Tools,  to find out the ADT delay setting the F4 used (on Revolver). It turns out the number is approximately 29.4ms.

Anyway, this ADT plug by Vacuumsound will help you get close to creating a nice natural sounding doubled vocal track. The end result isn’t as phasey as Waves “Doubler” program, and unlike Doubler, ADT is FREE, and you can download it here.


I was curious about the Beatles use of ADT (automatic double tracking) on Revolver.
Lennon loved it as it meant he no longer had to sing twice to have the double tracked sound.
On many songs, the original vocal and ADT’d vocal are mixed together “like “Taxman”.
But on some songs, like “And Your Bird Can Sing”, and “Dr. Robert”, they are panned hard left and hard right.
So I imported the songs into Pro Tools, and set upon finding out the amount of delay by running a ddl on one side.
It turns out the number is approximately 29.4ms. I can’t say exactly.
I did try to phase reverse one side and get it to cancel, but it wouldn’t.
Probably because they don’t sound exactly the same, as one has another tape generation on it.
Anyway, if you ever wondered how much delay ADT produced, now you know.

The vocal on the right side is the original, btw.


3 Responses to “Recording Vocals”

  1. music recording is tricky, good luck, everyone.

  2. Conan Troutman Says:

    That tight delay always makes me imagine him recording vocals in the bathroom, possibly whilst even in the bath, just wanted to share that with you.

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