Crossover Question with the 3134

[Loren42]

I am looking over the crossover used in the 4430 cabinet.

One thing that strikes me odd is the use of a ferrite or some form of iron core inductor of 2.6 mH in the signal path of the 2235.

Would an air core inductor be a better choice for the signal path? If not, why is that not the case?

Thanks in advance

[Robh3606]

You need to know what the DCR value is for the coil in question. There is no reason you couldn't use a good quality laminated steel core like the ones ERSE makes. I was face with using laminated steel cores vs. air cores to keep the same DCR value and the difference in cost was 4 fold for the air cores. Cost alone would be a significant factor.

Rob:)

[Ruediger]

I am looking over the crossover used in the 4430 cabinet.

One thing that strikes me odd is the use of a ferrite or some form of iron core inductor of 2.6 mH in the signal path of the 2235.

Would an air core inductor be a better choice for the signal path? If not, why is that not the case?

Thanks in advance

DC resistance is the reason. A high DC resistance would change the speaker's Qt value. A coil with a core can be much smaller than one without core and the same DC resistance. I think I gave You a link to the formula for the Qt value.

Ruediger

[Loren42]

Thanks, guys. Another piece of the puzzle falls into place for me. :)

[toddalin]

DC resistance is the reason. A high DC resistance would change the speaker's Qt value. A coil with a core can be much smaller than one without core and the same DC resistance. I think I gave You a link to the formula for the Qt value.

Ruediger


Or, JBL could have used an air core coil with heavier wire to overcome the resistance problem. But that would have cost more $$$. :o: