[JerryLove]

At the risk of over-simplifying a more complex problem: wouldn't the equasion for "high efficiency bookshelf" basically be "high efficiency driver (full-range to avoid crossover loss) combined with a large enclosure (likely ported) to provide as little resistance as possible"?

 

[JerryLove]

Actually: I was thinking that since not all drivers are equally efficient at a given range, that there had to be equalization in the crossover to "driver match". Since that cannot introduce new power (increase the power going to the less effcient driver), it must reduce power to the more efficient by converting it to heat: hence "loss".

But I've not built a crossover: perhaps I'm missing some basic physics. How do you prevent one driver from being unequal to another without selective reduction in the power flowing to it?