Does someone have a nice tutorial about NON textboox crossovers?

[Bricolo]

Hi all,


I'm not looking for textbook XOs (like 2nd order LR, with a notch filter, a zobel and a bafle step compensation, all calculated for a 8R dummy load) but for non textbook ones.

I've seen bigger-that-normal coils on a lowpass filter, that make both the low pass and the bafle step compensation. Or mistuned zobels, that give to the total crossover a steppier slope


I'm looking for an article that explains how to make such things.


Thanks,
Alex

[SY]

The equations are not solved in closed form, but rather, numerically. Go get some xover design software; the manuals will explain how to do it. The documentation that came with my (now old and creaky DOS version) CALSOD was particularly good. And, again, most of this is dealt with in Dickason's Loudspeaker Design Cookbook.

[Bricolo]

I have dickason's book, and I didn't see anything else that textbook crossovers.

Either I've read too fast, or the french translations misses some chapters



And I don't have any commercial speaker software. I've got speakerworkshop (free soft)

[pinkmouse]

Bricolo.

The standard equations give you all that you need. As SY said, you just need to understand mathematically what they are saying, what you want to do, and then you can alter or re-arrange them to suit.

I belive SW has a crossover simulator, but I may be wrong

[SY]

Alex, look through some of the worked examples in LDC. He does things like baffle step, notches, slope adjustments, and so forth- at least in the American edition. But there's still no substitute, IMO, for a decent xo CAD/optimization program and some hours spent in experimentation with topologies and values.

[Bricolo]

Originally posted by pinkmouse
Bricolo.

The standard equations give you all that you need. As SY said, you just need to understand mathematically what they are saying, what you want to do, and then you can alter or re-arrange them to suit.

I belive SW has a crossover simulator, but I may be wrong

Wich equations?


SW has a crossover simulator, you're right



SY: sure, there are examples of BSC, notches, zobels....
But I think you haven't understood what I was looking for: I don't want textbook crossovers examples

I saw some XO where there are
-mistuned zobels that acted like an additional order to the XO
-bigger that calculated coils, to add dome BSC to the lowpass
- series LR parallel to woofers (what are those for?)

I want some infos about that

[SY]

Dickason does some of that in his examples. But really, what you're looking for by its nature is specialized. If there's a tutorial, then it's textbook by definition.

The equations Al and I refer to are the transfer function equations. You can play with added terms, varying coefficients, and the like using standard pole-zero math. The tough part is fitting the driver complex impedance to a function, then doing the numerical solutions (it's doubtful that you'll come up with closed-form solvable equations) which is why I still suggest you spend a couple of hours with an xover sim program and see for yourself what some of the effects of component/topology changes are.

[Bricolo]

I'll have to read dickason's book one more time

are those example in the XO chapter?



I especially wanted to know the advantage of a "n"th order XO with a mistuned zobel compared to a "n+1" XO without zobel
or the advantage of a big coil compared to a normal coil + separate BSC

[SY]

Well, that's a VERY specific question, which Dickason probably won't answer.

If I could outlaw the term "Zobel." I would. It's just two more resistive/reactive elements to tune in order to hit a desired transfer function. That's why on the eighth day, the gods created speaker software.

[mikee12345]

That's why on the eighth day, the gods created speaker software

gods ,not a God?