For me, no matter how good your main monitors are ,theres no substitute for running a mix through run of the mill 'average' radio type speakers to make the final call ,if you have limitless wattage and bandwidth it very easy to over cook the bass end ,the moment you play such a mix on a humble boom box or car hifi and the cones start flapping you know its not right .
Ive been a big fan of active for many years ,but lately Im thinking of just returning to a passive x-over for my mid tops ,at best a digital crossover @96khz samplerate has a bandwidth of 48khz , yet a very good quality power amp could well have a -3db point of 500khz . Ive looked at Troels's site and he's very much into passive crossovers ,very high quality components though .I recently got a set of dynaudio audience 40;s 15w75 mid bass ,D260 tweeter , I plan to pair these to the venerable Haffler Xl600 ,passive line level filter on the inputs tailing off the low end below around 200 hz ,then re purpose two pairs of Behringer Truth monitors actively crossed over to fill in the low end , I'll wire directly to the power amp inputs of the bass units on the truths and use a bss fds355 to tweak things to match in with the Dynaudios . thats a lot of juice 2x450 into the mid highs ,4x150 into the truths . As I mentioned proof of the pudding comes from judgeing a mix not at 120 db spl ,but at what the average user will listen to it at . If your sitting in company and trying to carry out a conversation with music on in the backround anything above 80-90db spl and you have to start shouting to communicate. Its the first few watts that really count in that situation.Headroom or overload margin is always good to have ,in one studio I used to work we had a pair of Ns-10 powered by a macrotech 1200 ,we almost never lost a drive unit ,where a smaller amp driven into heavy clipping will take out a tweeter in a microsecond.