Why do vocal harmonies of older songs sound have that rich, “airy” quality that doesn’t seem to appear in modern music? (Crosby Stills and Nash, Simon and Garfunkel, et Al)

Question

I’d like to hear a scientific explanation of this!

[Example song](https://youtu.be/C7HP9Xkim9o)

I have a few questions about this.
I was once told that it’s because multiple vocals of this era were done live through a single mic (rather than overdubbed one at a time), and the layers of harmonies disturb the hair in such a way that it causes this quality. Is this the case? If it is, what exactly is the “disturbance”? Are there other factors, such as the equipment used, the mix of the recording, added reverb, etc?

EDIT: uhhhh well I didn’t expect this to blow up like it did. Thanks for everyone who commented, and thanks for the gold!

In: Physics

Answer 1

I see a lot of good info, but I didnt see anyone talk about this. When people sing in the same room the vibrations of their voices actually affect each other. When perfect harmonies are sung there are natural overtones created by the stacking of the sound waves. When voices are autotuned or electronically harmonized you are actually missing a lot of frequencies that natural harmonization would have, making the newer stuff sound flat and robotic.