Crossover orders question

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First-order crossovers are easy and cheap. The studio monitors I'm using have 1st-order on the tweeter (a cap) and nothing on the woofer, and they manage to be flat from 45hz-20khz.

Most of the time, though, 1st-order is chosen because of cost, and you see it in el-cheapo speakers.

2nd-order has some neat properties--the phase shift is 180 degrees, so you hook the drivers up out of phase and the phase comes out correct--and the highpass crossover keeps all potential excursion constant below the crossover point.

My question is this: if I cross over a tweeter 2nd-order at a reasonable point, I've guaranteed by virtue of the 12db/oct slope that it will not get overloaded; why, then, do people use 4th-order slopes? It seems like overkill.
 
Higher orders...

Have no idea why they are used.

2nd order is as high a I go. Choose drivers carefully, most times add a 1st order to the woofer (plus natural rolloff), some times nothing on the woofer and a 2nd order to the tweeter plus an L-pad. Works for me. Keeps it simple.

Seen some crossovers with 4th order and compensation circuits that would be lucky to fit in the box. I thought if you chose your drivers carefully, you should be able to dispense with all this stuff that seems to try and make up for driver's shortcomings.

At the moment I'm trying to get a grip on serial crossovers (Andy Graddon has been an immense help) as these are so simple though not so easy to implement. Worth a try though as could be very rewarding - you never know if you don't have a go. The use of 1 resistor, 1 cap, 1 inductor in a crossover for 2 drivers really appeals to me. But maybe that's just me.

Would like to here from those that do use higher orders.
 
SY

Could you please explain what you mean by:

"2. When you talk about how a loudspeaker measures, you have to specify where, especially with lower order crossovers."

The only measuring gear I've got are ears - it either sounds good or doesn't.

Thanks
 
4th orders seem far more common in subs

when you get down to the lower ranges in hz, you frequently need a steeper slope for best integration.

if you are crossing at say between 100 and 150, the mid simply isn't dropping off quickly enough (in many cases)

FWIW, biamping with a digital linelevel crossover and crossing at 146 hz, nothing integrated as well as fourth order L-R in my setup. I played with a number of slopes, orders and crossover points.


So I would say that _where_ you are crossing has a lot to do with what type of slopes you are thinking about using.

There's going to be a lot of difference between crossover points of say 100 hz and 3k.


regards

Ken L
 
rabbitz said:
SY

Could you please explain what you mean by:

"2. When you talk about how a loudspeaker measures, you have to specify where, especially with lower order crossovers."

The only measuring gear I've got are ears - it either sounds good or doesn't.

Thanks

If a speaker is flat in one point in space, it's unlikely to be flat at another- polar responses have all kinds of funny behavior. In the case of 1st order crossovers, the polar pattern is VERY poorly controlled, and arrival time differences can really hump up the frequency response; the first order network is exquisitely sensitive to zero delay plane offsets, so the vertical polar patten usually comes out even worse than the horizontal pattern.

The only *acoustic* first order designs I've ever heard that sounded uncolored and had stable imaging were 5 or 6 way designs.
 
1st order...

Thanks SY

1st order looks terrible on paper but there seems to be a cult following for these. Have heard some great sounding commercial speakers using 1st order on the bottom end (some early Richter's designed by Ralph Waters in Australia spring to mind). Maybe it's because they're not uncoloured that gives them their appeal.

I suppose the journey is not important as long as you get there in the end.
 
-I have used a 4th order to cut an aluminum cone woofer. So the tweeter that goes with it should have a 4th order crossover to match.

-Second reason, when using a 4th order, the interaction between the drivers is greatly minimised. this can be useful sometimes (ie, car audio)

-3rd reason, using a 4th order on the tweeter car be used to go low with a tweeter without distorsion.

F
 
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no cookbooks no predictions

Hello,

I would like to add that each configuration is unique. No rules.
Dont use ears before in the ballpark. Ears are the only and final tool to choose amongst competent crossover applications that satisfy basic criteria at least.
Just to find the golden compromise in a latest cheap parts two way homespeaker configuration of mine, took me 6 months to try between 10 technically sound crossover solutions. I dont try to scare you but at least know how things go.
There is no need to be as obsessive but at least experiment as much as you can afford. And...hey a PC card based RTA isnt that much of an arsenal to have.
 
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