Sonos Arc: As the central hub, it features 11 high-performance drivers, including two upward-firing speakers designed to bounce sound off the ceiling for height effects. It handles the front left, right, and centre channels.Sonos Sub (Gen 2): This wireless subwoofer provides deep, "buzz-free" bass by using two force-cancelling drivers. Adding the Sub allows the Arc to focus on mid and high frequencies, leading to a richer overall sound.Sonos One SL (Rears): These serve as dedicated rear surround channels. The "SL" indicates they do not have microphones, making them ideal for surrounds since the Arc already provides voice control via Alexa or Google Assistant.