週休八日My 8 Day Weekend – 哭枯 in amba TAIPEI XIMENDING 西門町意舍(2013/1/13) (by 玉米 謝)
The lounge is called Tingba (‘Ting’ means to listen). On Tuesdays and Sundays, the shows are done in conjunction with Legacy Taipei, (Legacy mini @ amba). On Fridays & Saturdays, they have a DJ. (the Lounge DJ program was created by Harlem Yu, and features different guest deejays)
Looking at the photo sets on the amba fb (linked above), I can see they also have live acoustic music in a separate cafe, and they occasionally have music out at street level. Tingba/Legacy mini is on the 5th level.