By Domi Watkins     As fans waited in anticipation for Pentatonix on Saturday, October 29, they were able to witness the beautiful chemistry between husband and wife Michael and Carissa Alvarado from Us the Duo who opened for them. Their cover of Marvin Gaye and Tammi Terrell’s “Ain’t No Mountain High Enough” and 2015 … More Pentatonix Concert Recap