What are these vintage vocal FX?

Question

I have two songs that I want to understand how the vocals were done.

Is this ADT? Stevie Wonder - Happier Than The Morning Sun

1. I understand there are actual double tracked voices occurring but there are moments where it sounds like a single affected voice. Is that ADT?

And this distortion? Todd Rundgren - Rock and Roll Pussy

1. Is it just a clipped preamp? Or some other outboard unit. These distorted vocals appear a few times on this record.

Answer 1

I believe this vocal was originally recorded as one vocal. A similar effect can be achieved by duplicating the vocal, then pitch shifting the duplicated vocal by no more -30 cents. Then you would add a delay to the duplicated vocal and adjust the delay to no more the 60 milliseconds (ms). Next step would be to pan the original and the duplicate track in different directions. As for the distortion I believe this was a gain variation from the vocal going into the preamp that caused Stevie's vocals to sound that way.

Answer 2

ADT stands for: Automatic Double Track (or Tracking). This is achieved by adding a short modulating delay to a voice or instrument. Since no human will ever sing or play the same thing with the exact same timing and pitch, the delay imitates the slight to sometimes not so slight differences in timing. By adding modulation to the delay the timing differences sound more realistic and add some needed pitch variation as well, which makes the effect more convincing and less robotic. This effect was originally done with analog tape machines but is now typically done in the digital realm.

it's pretty difficult to determine the. source or the distorted vocals on the Todd Rundgren vocals. This is clearly an analog recording and distortion could occur at the; mic, the preamp, console/outboard gear, tape machine (most likely part of the answer) back to the console/outboard gear during mixing. The also appears to be some sort of modulation effect on the vox towards the end of the song.