Wayne Parham Messages: 18786 Registered: January 2001
Illuminati (33rd Degree)
The current four π cabinet is exactly the same as what was used in the former Stage and Professional Series four π loudspeakers. The current four π with stock drivers is the same thing as what used to be a Stage Series four π, and with upgraded drivers, it's the same as the Professional Series four π. We're now using a DE250 tweeter instead of a JBL 2426 in the top of the line model though.
The crossover is different between compression drivers because the DE250 is slightly louder than the PSD2002. Notice the different R1/R2 values on the schematic (shown below).
Baltic Birch is an excellent material to build with. It's light enough that I'd go with the thicker stock.
Break-in is really important with the JBL 2226, but not as much with the Omega 15. What's difficult about the 2226 is it isn't so much that the new driver needs to be broken in once as it constantly needs to be broken in. The driver just really responds best when it is given a little bit of power. It literally loses low-end when run at low power levels, almost a negative Fletcher-Munson curve.
The good news is that the shifts between low-power and high-power operation never put it in a peaky underdamped alignment. It just basically lacks some bottom end when the power levels are low. If you're running subs, it doesn't matter much, as it blends well either way, hot or cold. The improved midrange more than makes up for that idiosyncrasy, in my opinion.