Cascading in Crossovers?

[Gavinator68]

Could someone please explain to the newbie ( me ) what this is, how it works, and what the benefit is? Thanks a million guys!!!

[Ron E]

Cascading is when the filter transfer functions are multiplied - same as connecting ACTIVE filters in series. Example: Two 2nd order butterworth filters cascaded makes a 4th order linkwitz riley. Passive filter cascading is not so simple because the components interact.

If you don't understand that, you probably don't need to know. Do you have a specific application in mind?

[Gavinator68]

I was looking at a crossover where the cap value was the sum of 4 or five caps together and was curious what benefit it offered and how it would be implemented in a crossover design. Does it work for both low and high filters? Is it justifiable in terms of cost vs. performance? What types of caps need to be used in this arrangement for best results? Finally............what about winding my own inductors? Is it worth the money to have the largest gauge possible to gain minimum DCR?

[sreten]

Ron E is very much on the money here with what he says.

What he doesn't point out is forcefully enough is cascading has
no basis in reality as a technique, it doesn't have any advantages
/ disadvantages at all compared to correct technical terminology,
that is except for marketing men who like to confuse people.

(Except for active crossovers, which are formed from cascaded
2nd order sections, here different cascaded topologies affect
the maximum headroom, but there is no alternative to the
cascaded topology, so how can there be (dis/)advantages.)


sreten.

[sreten]

Paralleled capacitors (or series !?) is not cascading.

Inductors need to be wound to a sensible DCR value
for the application, for some inductors low DCR is
pointless, e.g. in a LCR tweeter impedance circuit.

sreten.

[Gavinator68]

What I think I was looking at were three caps wired in parallel that were in series with the tweeter. Is any of this making sense? Remember .................I am a newbie!

[Ron E]

When capacitors are connected in parallel, their values add together. Adding up multiple smaller values also has the effect of reducing ESR at the same time, but with good quality caps (Mylar or Polypropylene) ESR is not really that much of an issue.

If you want to know more, do a search for basic electronic theory and series or parallel combinations of capacitors, inductors and resistors.

[Sheldon]

Originally posted by Gavinator68
What I think I was looking at were three caps wired in parallel that were in series with the tweeter. Is any of this making sense? Remember .................I am a newbie!

Sometimes done because three small caps can be cheaper than one big one of the same quality.

Sheldon