SabrinaX Sub-Crossover

Thanks again everyone, excellent advice for me to work with. 

In room measurements are the best way to integrate subs. The in room response of the Sabrina speakers is more complicated than the specified bass roll-off and subs can help correct it. I do not know if ARC/PBK is powerful enough for good measurement feedback or not. It certainly could be. With in room measurements setting the crossover point is easy with some experimentation, especially with speakers with decent LF extension, like the Sabrinas. 

60hz with a highpass is a good starting point. Basses on the stereophile measurements of the Sabrina X, the woofer is taking a dive at 70hz. There is zero chance an 8” driver will outperform subs at 60hz-70hz. 

I read more on using ARC Genesis. It is highly regarded, at least from TheAbsoluteSound. 

@upstateaudiophile placement is critical with Wilson speakers. I would recommend setting up and dialing it all without the subs first. Look into acoustic treatments as well. Introducing limited range bass traps and treating the reflection points was a notable improvement in my room with the Sabrinas. After you dial it in, start integrating the subs, if you still think you need them.