"A capella" is a voice, or voices singing without instrumental accompaniment. Usually voices singing, harmonizing and mimicking instruments.
I do really enjoyed this song. I thought it was well done or even better than the original. But I kinda have a really hard time believing that as if it is just voices and mouth. The question is, if it is so A Capella, why is it digitally re-mastered? I still prefer the acapella done by Sam Tsui!
This sounded so fake... compared to.....