Though Apparat (aka Berlin-based producer Sascha Ring) is best known for frayed-out beats, his most recent album, Walls, has a dreamier, more ambient feel — full of slow, burbling sounds and vocals that verge on synth pop. For the Walls tour, Ring felt that a concert-style performance better suited the album's quiet atmospherics, so he recruited electro-funk specialist Raz O'Hara (on piano) and jazz drummer Jörg Waehner to join him. Tonight, the Apparat Band weave together mellow analog and digital layers at the Knitting Factory.