This graph shows the impact of tri-wiring the system with the 1ohm cable and applying the compensation at the amplifier terminals. The drop in output is close to a uniform 1db, much better than for the single wire case.

The exception to this is right at the mid/tweeter crossover point. Note that it is almost unchanged at this point. At the 2k and 3k points it is down by only 0.5 db. This would very likely be a noticeably change in the perceived performance of the system.