What difference does the "order" make with x-overs

This is very hard (impossible I think)to explain in a short reply at a forum. For a decent short explanation (12-13 pages) try True Audio. www.trueaudio.com/st_mr1.htm. There are two parts to this article. the second substitutes "mr2" for mr1 in the original site.

Another short one is AudioControl at www.audiocontrol.com/techpapers/techpaper102.pdf

If you want more buy Vance Dickason's book Loudspeaker Design Cookbook.

You might also do a search at www.madisound.com (one of the better diy speaker building forums)under various words such as 2nd order, 3rd order. Some of the most common filters are given names Linkwitz-Riley, Butterworth, Bessel. Use those names too. There is a wealth of info at the Madisound forum on this topic and the proper use and effects of each type of filter.

Good Luck.

I remain,

One short addition to Ezmaralda11's fine explanation. An Octave is a doubling or halving of frequency. 20hz to 40hz is an octave. 40 to 80, 80 to 160 are also octaves. 3200hz to 1600hz is an Octave going down.

If a crossover is 2nd order it is going down 12db per octave. If the crossover is 2nd order and set for 3200hz it is going to roll off 12db by the time it reaches 1600hz. This is actually a bit of a simplification but it gives you the general idea. Read the articles I mentioned in the other post for a little more info.

Cheers,

Your question has been pretty well answered above, so I won't elaborate except to add one point. As noted, the higher the "order" of the crossover, the more severe the roll-off. What was NOT mentioned is that as the "order" of the crossover goes up (say, from first order to second order), there is also a phase shift. The higher the "order", the greater the shift in phase. This can present a real problem to properly integrating the drivers. Thiel and Vandersteen both use first-order crossovers because their speakers are designed to be time and phase correct -- so, using a first-order crossover results in fewer complications with phase shift.

As is always the case, Sdcampbell's opinion is the kind of offering that proves he is a real world guru in this hobby.

One thing that I would like to add to his wisdom is that in addition to the issue of integrating the drivers into a "system", as the order of crossover goes up, so does the difficulty in driving the loudspeaker. I cannot deny that a more complicated crossover looks impressive, on paper.

However, in reality, each component in a crossover network acts as a "spring" to an amplifier's power output. If you will, a speed bump. Requiring more and more current to overcome the crossover, to get the drivers moving. Often, brute force solid state is the only way to go. A large number of this type of amp can sound etched, shrill, slow, ponderous, overripe, bloated, hashy, or electronic.

In my opinion, the more simple a crossover topology, the closer one is to the amplifier itself. The closer one is to the music itself. Not always a good thing. Especially, if the upstream components are not musical, natural, or grainless. But, for those of us with an appreciation for tubes, it is EXACTLY where we WANT to be.