I'd vote for the first orientation, which keeps the end of the lower steel core (from where the magnetic field emerges) as far away as possible from the air core inductor.
In the first pic, the steel cores have parallel axis, which is not ideal, but is mitigated by the distance. In the second pic, the axis are perpendicular but it doesn't matter because of the asymmetry: the coupling will be strong, and the distance is small.
In addition, the first configuration is more favorable regarding the air coil, which is why I vote for it
In addition, the first configuration is more favorable regarding the air coil, which is why I vote for it
I have seen pliers located about one inch from such laminated steel core inductor vibrate on a high level drum beat (its was a brutal load situation with passive 600uF/20mH "boost" into a little Karlson box with Kappa 12a.
Are there studies online and free which cover modulation effects from mutual coupling in multi-way crossovers?
Are there studies online and free which cover modulation effects from mutual coupling in multi-way crossovers?
I would arrange them on your bench, wire them in series and measure the inductance. Whichever way measures the most has the greater coupling.
Although in this case there is only one air-core coil, if there was a mix of air- and ferrite-cores, wouldn't it be more important to place the air-cores at right angles than the irons? I've read this is because line of flux are much more compact in iron-cores so less prone to crosstalk.
When I fasten three air-cores on a cabinet, I even put the flat one on a little riser so it will be on the same axis as the vertical one. An iron core is nearby, flat, where there's room.
When I fasten three air-cores on a cabinet, I even put the flat one on a little riser so it will be on the same axis as the vertical one. An iron core is nearby, flat, where there's room.
Do you mean the lower the inductance , the less stray coupling?
Can't a given combination of relative orientations (ie. connection polarity or coil turns orientation) reduce measured inductance through cancellation ?
Thanks
You can effect either increase or decrease by simply reversing the polarity relative to each other. The point is to try to identify the relative contribution. If it makes it easier, place them far apart but in series to see their combined individual inductances, then move them and see which orientations cause the biggest difference (either up or down, depending on your polarity).
AllenB, that would be a great way to test an inductor layout. IIRC, 2(pi)f(l) = inductive reactance. So, if I have a dead frequency generator, and am using the generator app on my phone, could I set it for one v, at a f where all the inductance in series would have impedance...I could then arrange them for least v drop. That would mean least mutual inductance, is that correct?
I mean, how about 150 hz, at a constant 1 vac in. All inductors to be used tack- soldered in series, connected by stranded hookup wire a foot apart. Use masking tape to place the coils within the crossover for the absolute min 150 hz vac out. Then, fasten them "for real." Unsolder the hookup wire, put the caps and resistors where there's room, then connect that bad-boy "for real!"
Yes, if you had them in series with a test resistor so that their reactance would translate into a change in Voltage. The reactance would go either up or down as mentioned above.
(and for anyone reading if I wasn't clear before, the inductors won't be in series in the crossover, but only for the purpose of testing their interaction)
(and for anyone reading if I wasn't clear before, the inductors won't be in series in the crossover, but only for the purpose of testing their interaction)
What exactly is supposed to be wrong with #4 and #5? The cores are at 90 degrees to each other, same as in the following #6 and #7.
I did some testing on this. If you have an LCR meter you can easily test which configuration is better or if both are equally fine. Just test them really far apart to get the baseline result, then place them on the board and see if the value changes.
The corrected measurements start at post #10:
https://www.diyaudio.com/community/...n-core-inductor-from-15-woofer-magnet.384037/
The corrected measurements start at post #10:
https://www.diyaudio.com/community/...n-core-inductor-from-15-woofer-magnet.384037/
