Common information for components of a passive cross-over.

Capacitors.
For high capacity is necessary to change the capacitor (A) with :

• B) Electrolytic capacitor not polarized with capacitor in parallel.
• C) Two electrolytic capacitor polarized in antiseries more a capacitor in parallel.

The lower capacity (100 nF) in parallel serves to compensate the parasitic inductance of the electrolytic capacitors which tend to get higher with the increasing of the frequency.

The special electrolytic capacitors for switching power supplier are good also for realization of audio crossovers because particulary treated about parasitic resistance and inductance. They are realized for work also in higher frequency than the audible frequency.

The lower capacity in parallel is advised also if are in use not polarized capacitors, also this kind of capacitors, considering the high capacity in use, have the same problems of the electrolytic capacitors, also if in a minor way.

Inductances.
Inductances with an high number of coils have also an high parasitic capacity, to limit it :

• A) Use more inductances in series with sum of the values equal to the needed.
• B) Adopt inductances winded on a core reduce the number of the coils, but pay attention that core must be adapt at the frequency used and which core must not saturate itself.
• C) Wind the inductance in spaced layers is the better solution on all respects but also the most expensive (used in rare fine HI-END applications).

When there are multiple inductors closed but not connected in series or parallel, to avoid an inductive influence is important to direct them at 90 degrees on x, y, z axes, in this way the inductive coupling will be minimal.

Avoid connect the inductors of crossover filters near transformers or others alternated magnetic sources.

Resistors.
About the resistors is better use the anti-inductive (not Wirewound resistors). Really if we are talking of a few ohm value, the parasitic induction is so little which doesn't create problems at the audio frequencies, is important exceed in the advantage to obtain the better possible stability of the value.