It's coming back like you would not believe and i'm in heaven!!

Mike Tomkins
Peter Hollens
Sam Tsui
Kevin Littlefield
DeStorm

Just to name a few that i've recently found on YouTube.

Found any others that have blown you away with their A Capella talents?

As much as I love this, I struggle to call it a capella. It's brilliant, it's fascinating, but it's also hyper-produced, which is kind of the opposite of a capella. :(

A Cappella music is solo or group vocal or singing without instrumental sound, or a piece intended to be performed in this way.

It does fall under the definition of A Capella. It may be pushing the limits of the traditional way it has always been viewed, but it non-the-less does fall into this category. It is not A Capella in the style of the "Doo wop" "Barber shop Quartet" o even close to what was done in the Renaissance Days (when it was mainly used in Churches), but it is still A Capella.

And what do you mean by "hyper-produced" ... as in they layered their different tones over one another? I'm sure they could still make the same songs if they had enough talented people in one room.

I really just wanted to give my opinion and not get into a debate about what is and isn't a capella, but here's my take on it:

A capella means "to the chapel" or "to the church" right? It's a performance art based on actually singing, without accompaniment, in front of people (parishioners, originally) and that's why I have a difficult time calling this a capella. As amazing and just plain cool as the music Mike Tompkins makes is, it still requires hours of production and no small amount of studio equipment (he uses Melodyne for his pitch adjustments, hence the "Bass -1 oct" and "Synth +1 oct" etc) Even if you were to take a dozen perfect clones of Mike Tompkins, they couldn't make this music live without synthesizer support, and that pushes it outside the lines of a capella, in my opinion. (It's a moot point, however, as there's no such thing as pure anything anymore, and the term will simply be expanded to cover this, too, and then I'll just have righteous indignation at the fact that nobody has standards anymore, but I digress...)

I don't want to take anything whatsoever away from these artists. This music is absolutely awesome, and I love it. I just don't think it's a capella, and should be called something else that more accurately describes it.

tl;dr-

• A capella is church music, for voices only, to be performed live
• Mike Tompkins' music could not be performed live without synth support, even if you had a hundred of him
• This isn't taking away from the greatness of the music
• It's awesome, but not a capella, give it its own name

I think Mike is the only one that does any alteration to the natural tone of his voice. The others make do with beatboxing, vocal manipulations and self toning.
But I do see what you mean, though I am not so strict on my take in what can and cannot be A Capella.

I've never been too impressed or interested in church going A Capella, so found no true joy in that music. Seeing something so dated and unique brought into the world of the 21st century just amazes me. Though I suppose if they came up with a new term for what to call what these fine men and women create, then i'd not complain at all.

However, A Capella truly is the closest thing to describe what these talented artists create.

And sorry if this turned into a debate, i've always been one that has enjoyed the occasional in depth conversing; over idle banter.