" wrote:
OK - some basics:

a) very nearly every speaker capacitor is non-polarized. Why? They are
designed to work in an AC (alternating current) environment, albeit at
rather low voltages.

b) as capacity increases, the cost of a non-electrolytic increases
significantly per uF, far more than with an electrolytic cap.

c) non-electrolytics tend to be larger than electrolytics as uF increases.

d) manufacturers, therefore, favor electrolytics as a means to lower
costs and lower real-estate requirements.

Those are the most basic reasons that you will see electrolytic
capacitors in speaker crossovers. "Voicing" while a very real concern
will not be materially affected by changing out one electrolytic for
another as the tolerances are pretty sloppy as compared to
non-electrolytic capacitors, and even low-end manufacturers would do
some basic screening. However, if you choose to substitute a large film
cap(s) for an electrolytic, some experimentation may be required as these
days, the tolerances for film caps are commonly less than 2%. As compared
to as much as +50% for electrolytics.


Sometimes you need really big values. I have measured many electrolytics
that are very close to marked value, at least ones in good shape.

http://www.updatemydynaco.com/pictur...rAnnotated.JPG

This is a crossover from a Dynaco A25 speaker. Well respected speaker
with excellent drivers, but from a manufacturer that pretty much did
everything in the cheapest possible way. One electrolytic cap, and a
bunch of sand resistors.

http://www.classicspeakerpages.net/I...4 b6b4d7b.jpg

This is a crossover from an AR4x speaker, contemporary to the A25, and
also well respected. But from a manufacturer that did not do things in
the cheapest possible way. Note the inductor, and non-electrolytic cap.


Some simple caps change crossover points with variable attenuator in
series. So you get level and phase change at the same. Not great idea.

There are many ways to get there.

Peter Wieck
Melrose Park, PA