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’m late to the party but something I don’t see mentioned much is that a lot of it is a very clear stylistic trend in arranging music. Big thickly voiced chords with lots of 3rds are not in vogue. The trend by and large across most popular genres is more toward open, powerful, clean chords (or just single note lines) that do not contain a lot of harmonic material. I say this as someone who does it for a living – if I layer up chords with nice fat harmony I get the note “it sounds old” or “cheesy”