 In addition to his solo concerts, he performed from 2001 through 2003 with Jake Hess, Wesley Pritchard, and George Younce in the Old Friends Quartet.After the Old Friends Quartet disbanded due to the ill health of Younce and Hess, Haase founded the group Signature Sound Quartet, Inc.The group was rebranded by their record label, Gaither Music, to "Ernie Haase and Signature Sound", to take advantage of the platform of The Cathedral Quartet and Haase's popularity as their final tenor.