Please stop doing it chaps! Maybe I sound like an old fuddy duddy? But come on!
The most powerful vocalists on the planet don't use it, or very sparingly. There is an excellent reason why.
If you respect the voice as an entity in its own right, why not let it be what it is?
It's not the human-machine interface at all that bothers me. There should be more!
It's the fact that the machine part is actually a human in disguise.
Autotune basically locks you in to some human's concept of sound--Bach's to be precise (equal temperament), now hardwired into every blasted piece of readily available synth software out there, unless you are very lucky. This concept makes everything turn into sepia. And you are just retweeting some 18th century organist's mind. If you want colors, you have to not do that.
Obviously your actual physical voice doesn't work according to some 18th century guy's concept.
Here is a list of alive people who don't need to use that crude auto tune, ever ever. Cos they know how to sing! And what voice is.
John (my mate from the erstwhile Moke)
Surely there are more but these are my bests.
The best vocals make you think all my concepts are erupting.
Actually here is Moke, with my favorite song of theirs, co-written by my brother Charlie. There is a tiny use of auto-tune, in one spot, but not to make him integrate with the mechanized structure of a horrific wrongness. Also, the lyrics, wow. “Ship of sound...” “[M]y money is slow and my mask is a mirror for delivering the devil down...scuse me while I'm thinking of something more insulting/These are the dreams of the pale in power..."