Build an active system around the AC650.
Pick a 2-way or 3-way topology and a driver for each way. The AC650 gives every driver its own channel and crossover, so you balance the system in software. We'll show how much power each way actually pulls, the headroom you have to spare, which driver sets the loudness ceiling, and a starting crossover to refine in AirDSP.
Everything below is calculated for a stereo pair, both speakers. Each way uses two channels, left and right, so a 2-way pair takes 4 of the 6 channels and a 3-way pair takes all 6.
Headroom is real SPL math (sensitivity + power + distance), not a measured response. Per-channel power depends on the driver's impedance: about 56W into 4 Ω and 34W into 8 Ω (measured). SPL is figured against each driver's 2.83V sensitivity. All six channels share one power supply (252W Standard, 200W Deluxe, the Deluxe trading a little power for a lower noise floor), which caps total output at roughly 220W and 180W, so the loudest driver runs full power and the rest draw less once trimmed to match. The total only matters when every band peaks at once. Figures are from independent bench measurements (see the report); the latest production AC650 runs a touch higher. Crossovers are starting points to refine in AirDSP with a measurement.