Inductor difference

[Dave A]

So I see the same values for air coils and iron center coils and autoformers. What precisely is the difference here and why? For instance I have an LF crossover in a pair of KP-450's and the schematic shows a 2.75mh value. I see Bob uses an Autotransformer for the KP-456's he builds and this 450 bass bin is the same one. However Klipsch substituted 4 small air coils for this in their factory LF crossover and I assume to reach the same value with parts on hand. Does it really matter how you reach the goal of mh? I do see differing resistance values depending on what you are willing to spend and have no idea how that affects things either.

[Alexander]

An air coil will always have a higher DCR than an iron/laminate core coil of the same AWG by way of using more wire to achieve the same mH value. The down side to iron/laminate is they get saturated quickly so they are generally limited to under around 3000Hz. The positive is they have a lower cost for the part.  Conversely an air core do not have the saturation issue and cost more so they usually reserved them for HF.

The transformer and laminate core are essentially the same thing and iron cores usually do not perform as well.

 

 Lower DCR is always better (higher Q) unless a certain DCR value is desired by design.

[Guest wdecho]

Inductors in our x-overs with our efficient speakers are not going to saturate. Big air coil inductors are mainly eye candy. 

[JohnA]

Mr. Paul said the K-horn woofer inductor began to saturate at 63 watts.  It won't happen often. 

 

Iron-core inductors also hold their magnetic fields very close, so you can locate them closer without one affecting the other.

[Alexander]

3 hours ago, JohnA said:

Iron-core inductors also hold their magnetic fields very close, so you can locate them closer without one affecting the other.

That also applies to laminate core.