Selecting drivers is an art more than a science, although it uses some science. I selected drivers by picking from spec sheets, and knowing manufacturers. I first picked the Vifa PL18WO-09 and the LPG 38T. 

I picked the Vifa because the specs on it are virtually perfect for a monitor. Good high end, great power handling, and adequate bottom end. It's a bit bigger than usual for a smaller speaker but the above average high end works well in this design.

I picked the LPG because I wanted a larger-than-usual tweeter to allow for better power handling and to simplify the crossover design.

If you've read the earlier pages you will note that the original testing knocked the LPG out of contention. Measurements were so-so and listening tests were similarly so-so. I originally switched to the Vifa D27 (a tweeter I've used before) but when my driver supplier (AudioLab of Georgia) got in the Vifa XT25 I tested it as well and ended up using that tweeter.

So, the final driver complement in the monitors is 2 Vifa PL18WO-09 and 1 Vifa XT25TG-30. The drivers alone cost approximately $180 per speaker. These are the high-end drivers from Vifa. The middle-class Vifa drivers would cost about $60 per speaker and work just about as well (with a bit less bottom end and a bit hairier crossover region).

To make this simpler to read/understand all of the discussion in this section assumes the final driver complement and ignores the mistakes / retries (those are written in earlier pages).