I have always recommended that a person consider one of two options:

1. Build your own crossover from the schematic provided, or
2. Use the Eminence PX-BII1K6 crossover and add compensation components R1, R2 and C1 as required for the desired amount of HF attenuation. In most cases, the Eminence crossover is not modified at all, and compensation components are simply built into the tweeter cable assembly. When using certain JBL woofers, the PX-BII1K6 is slightly modified and for 2" tweeters using an 800Hz crossover, the PX-BII800 is used as the "base crossover" instead of the 1K6.

But I now provide a third option. I now offer completed crossovers assemblies as shown on the Pi schematics. This will ensure that the crossover installed in your loudspeakers is 100% optimal. In fact, this is appropriate for any DIY builder using a 2 way system having compression horn tweeters. One should simply know the amount of tweeter attenuation required, and order the right part for the job. For example, if you are using a 98dB woofer in a bass reflex cabinet and you are also using a tweeter that generates 110dB in the horn, then you need 12dB attenuation. If the crossover desired is 1600Hz, then you will need the 1K6a012dB crossover. Pretty simple part numbering scheme, really.

More technical information about these crossovers can be found in the post called "Spice circuit analysis".