Sonos Arc Ultra Dual Sub In-Ceiling Surround Package (8")Whats Included Sonos Arc Ultra soundbar 2 Sonos Sub 4 wireless subwoofers Sonos Amp Pair of Sonos 8 in ceiling speakers (rear surrounds) Maximum Impact, Fully Controlled The Arc Ultra provides detailed, immersive sound with precise dialogue and expansive Dolby Atmos effects. Adding dual Sub 4 subwoofers takes low frequency performance to another leveldelivering deeper bass, improved balance across the room, and greater control at higher volumes