I am new to this site and its been very helpful so far.But it seems the more answers I get, the more questions I have.I guess its called learning.My question is[ If a cap in a crossover circuit is a bypass type such as in a second order woofer circuit,where its just rolling off the upper frequency faster,does it have to be as high of quality as a cap that music passes through?] I would think a first order cap for a tweeter or squawker would be much more important.So you could buy $50 caps for the important ones and $10 caps for the less heard caps.I hope this makes sense to you out there but I would rather put the money where it counts.Or,maybe I am missing something and the GURUS out there will inform me. Thanks Bill

It's not the best idea in the world to save money on parallel elements in a crossover.

Inexpensive electrolytics have high ESR, poor current capacity, dry up sooner than film types, and can be a problem with bass-midrange drivers having peaks above the pass-band (metal types, as well as some others).

It's a real drag to have to replace electrolytics after ten tears or so, and then hear what a change there is (and wonder how long you've been missing some of the music).

The poor dielectric absorption of electrolytics also contributes a backround 'haze' to the sound during quiet passages in the music.

I now use the most inexpensive film types that have non-magnetic leads.

I've read that type of thing too.  The statements pertain to higher order crossovers where one or more L or C are connected to ground.  The proponents seem to think that part of the signal is shunted to ground and therefore (since it is drained off) that path has less influence than the path with components in series.

In my view, that shows a lack of appreciation of the function of the circuit.

If you look at a second order filter, the L and C form a voltage divider with the the speaker attached at the center.  In a second order low pass (woofer) the L connects to the amp and the speaker (in series, as it would be in a first order)  But the L is loaded by both the speaker and the cap across the speaker,

Let's look at a classic voltage divider with two resistors.  Both resistors influence the output of the voltage divider.  No one would say that a faulty resistor on the ground side has no effect.

Similarly, the shunt cap in a woofer crossover HAS to influence the output.

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It is interesting to look at the value of the L and C in a second order crossover.  You can use the tables at Parts Express.  I'm sure you'll find that at the cross over freq, they both have the same impedance.  You can do the math of Zl and Zc.  I believe you will find their impedance  (each)  are 0.707 of the assumed load.  Therefore, at the crossover freq, both the L and C have equal influence.

In the first order crossover the impedance of the single L or C is equal to the impedance of the load, BTW.

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I always love to point out something which one of our moderators called to our attention years ago.  Suppose we have a second order crossover.  If we disconnect the speaker, there is a series L-C across the input.  These resonate to form an impedance notch down to zero ohms (or the internal resistance of the inductor) at some frequency.  It should be the crossover freq IIRC.. 

Therefore it is potentially dangerous to the amp to run higher order (other than 1st) crossovers with a disconnected or blown out speaker.  At some freq, the amp is seeing a dead short.

Gil

"At some freq, the amp is seeing a dead short."

Having to replace the woofer in a Heresy II, then repair the network, and then the amp, I can vouch for that!

Several people on these forums offer crossovers and upgrade kits.  Following their choices, you will have a reasonable balance of cost and performance.  Matching values is desirable for both channels to sound the same (not to be confused with tolerance).  While 10% tolerance may be adequate for low order crossovers, steeper slope designs may require either 5% or 1% to retain the proper filter shape and transient response.