Defending the As-Yet-Undefended: The Manhattan Transfer

I was going to say cooler than the Swingle Singers, then I remembered the Swingle Singers worked with Berio - the composer, not the olive oil. Definitely cooler than the King's Singers though but, then, what isn't? OK, Instant Sunshine.

The King's Singers appeal is their relentless assault against the idea of what is "cool" about close-harmony singing.

I mean, this is hilarious and awesome, assuming you like madrigals:

https://youtu.be/sCssYhnSOeE

(I am admittedly biased because one of my college choir directors is good friends with Simon Carrington but I am and always will be pro-King's Singers)

their album covers inspired those ugly-yet-endearing '80s broadway posters (zebra patterns, red lips, top hats, loud colors on black backgrounds) you still see in decrepit last-holdout times square fast food joints and rolled up in discount boxes at hell's kitchen framing/mounting shops.

wow, right down to the long instrumental introduction. Blatant

Kings Singers stomp all over Manhattan Transfer. They certainly have their whimsical material which is often performed to showcase their virtuosity and there's no doubt that's very uncool. But their classical stuff and their more serious repetoire can be genuinely moving.
Love this:
https://www.youtube.com/watch?v=lRIrqiwkdYs

They have a stellar arrangement of "Little David, Play on your Harp" that my kids love:

https://youtu.be/1Cu_jBAYpyE

That's all very well but the first post claimed about Manhattan Transfer that There is NOTHING less hip than this...

Already answered upthread - Instant Sunshine.

This video, for "Soul Food to Go," from the Brazil album (1987) touches a nostalgic nerve in me. The song was co-written by Doug Fieger of The Knack, of all people

https://www.youtube.com/watch?v=4Gc9xVRLFHU