Why not go crossover-less?

I planned on using two amps, same name less power.

Could the following be another reason the cross-over is placed in the speaker? When the x-over is placed in the line stage is it more likely that errors will be more pronounced because of the amplification of any errors?

No, the signal gets amplified as well, so any "error" introduced by a crossover that is in front of the amplifier will remain in the same proportion to the signal after amplification.

I found the speaker that'll stay with me for a very long time, I also found which amp I will use to drive them. If a dedicated cross-over was to be designed knowing the input impedence of the amp and output of the preamp could the line stage cross-over outdo the other approach the speaker cross-over way?

It sounds like you are referring to a passive line-level crossover. That MIGHT be within reason for a speaker requiring a simple first order crossover network (6db/octave), or perhaps even a second order network (12db/octave). However, anything higher order or more complex than that is likely to result in excessive signal loss. There would also likely be an unreasonable degree of sensitivity to cable parameters.

And more fundamentally, who is going to create this dedicated design? There are at least three, and perhaps four parties involved (if the preamp and power amp are manufactured by separate companies): The speaker designer, the amplifier designer, the preamplifier designer, and the user. The only party likely to have a complete understanding of the crossover requirements is the speaker designer, and he would have no incentive to create a crossover design that would only work properly with a particular set of electronics (unless of course, it was part of his own active speaker design).

An active line-level crossover, on the other hand, would eliminate the signal loss issue, greatly minimize the cable sensitivity issue, and potentially provide enough flexibility to be a viable option with some speakers. But of course it would add a costly component to the system, which would still be unusable with many speakers.

Regards,
-- Al

Something like this?:

http://www.tactlab.com/Products/MS2150XDM/features.html

>Would there not be an advantage to place the crossover in the linestage instead of the speaker?

Other than marketing there's no good reason not to. The cross-over function doesn't change with output level; you can use all-pass filters to match phase independently of baffle configuration; you get the same peak output level with smaller heat sinks and power transformers; big inductors get replaced with low wattage resistors (not $.10 each in small quantities with 1% tolerances), and big capacitors small ones (under $1-$2 for 2% tolerance film caps) due to the higher load impedances. Even when starting with your existing amplifier, an active cross-over+power amp+power supply can cost less than the large high-quality reactive components needed for a passive cross-ove.r

More accurate, more headroom, and lower total system cost.

My main system is actively tri-amplified, the small bedroom setup actively bi-amped until I get enough shellac on the new woofer enclosures for the tri-amp upgrade.