Coil selection question

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Hello everybody:

In my new project 3 way Xover design I have one question due to Space limits for the Xover, I have to choose between:

1.- iron core coil 3,9mH/0,36 ohm/1mm copper wire(18AWG)

or

2.- air core coil 3,9mH/3,45 ohm/0,50mm copper wire(24AWG)

I will install the iron core #1 for the bass low pass secction and I need to install ANOTHER coil in the band pass section for the mid section to avoid low frequencies.

Whats a better solution #1 or #2 ?
thank you
 
Hi,

The iron core it is on close magnetic circuit or open magnetic circuit?

What power the speaker talking about?
Can you provide some photos for iron core (with some dimensions)?

I think it's usually overrated core saturation. By making an optimal choice of the coil / core saturation can be avoided easily.

But still it is not recommended to use at frequencies too high, usually only filters for bass in three or more ways, that under 1-2KHz.
 
.............. for the Xover, I have to choose between:

1.- iron core coil 3,9mH/0,36 ohm/1mm copper wire(18AWG)

or

2.- air core coil 3,9mH/3,45 ohm/0,50mm copper wire(24AWG).............
These are not the same.
0r36 and 3r45 will operate differently in a passive filter.

If you want to swap between them, then the inductance and the resistance MUST be the SAME.
 
I know there's a big difference between the 2 different coils, but maybe depending where it's gonna be placed could work.

I attach the theoretical Xover (without Lpad and Notch filter)
The question is regarding L2, because L4 will be Iron core.
 

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  • Xover.png
    Xover.png
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Your crossover filters are using Inductors.
BUT !!!!!
the parasitic resistance of the Inductors is missing.

Your model to predict the filter behaviour must include the parasitic resistance.
Then you will see the difference that 0r36 and 3r45 will make to your filters.

Change your model in the software.
 
Plenty of high end speakers using iron cored inductors for woofer, for values that high air core just isn't suitable, chances are you're trying to put as little DCR in front of the bass woofer as possible. Using a 3.9mh inductor with DCR of 0.285Ohms is going to need something like 2.5mm wire for an air core. If I remember rightly those cost about £150 a pair from mundorf. That's not the kind of money you should ever be spending on a pair of coils. Alternatively a pair of drum-cores will cost you £20, and although in theory they will saturate, in reality you'll probably NEVER hear it - and I'd stake a lot on that, a lot of very high end speaker manufacturers have staked their reputations on it.
 
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