Hi Wayne, I've got a couple of questions. I plan on building my 3 Pi speakers with both the upgraded drivers and your H290C horns. Do I have to modify the crossovers for them, or just proceed with the original design?
The crossover was changed slightly in 2010 when the H290C waveguide was introduced. It also uses components specific to the drivers chosen. So look on the crossover schematic I sent you in February - the current version - to see what values should be used for your chosen drivers.