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Old 26th August 2012, 03:29 PM   #11
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Well, to me it would be a matter of the damping factor (DF)
If an amp has a (assumption) DF of 1000 it's output impedance is 0.008 ohm
Add 0.1 ohm for the speaker wire and the DF drops to 74.1, not good
Add the 2 coils DCR (0.22 + 0.11 ohm) and the DF is 18.25, not good at all!
At this DF the speaker will do what it wants to do, not what the amp tells it
In a low power system that will not matter much, but that is why high-power systems use active Xovers and multiple power-amps. E
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Old 26th August 2012, 05:04 PM   #12
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Before I get clobbert about my post (#11): I ignored complex ZCLR references as these would be meaningless without the full details of parts used and a schematic. E
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Old 26th August 2012, 08:53 PM   #13
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Quote:
Originally Posted by mickeymoose View Post
Before I get clobbert about my post (#11): I ignored complex ZCLR references as these would be meaningless without the full details of parts used and a schematic. E
I need it for very simple 2nd order Butterworth passive crossover.
Therefore, 0.22uH/0.11Ohm RDC + 0.10uH/0.07Ohm, sum will be 0.32uF/0.18Ohm (I can live with that), but what abouth quality of sound
I have Mundorf colis CFC14 0.22uH(and if possible I would love to use them), dont want to waste money buying coils of 0.10uH and connect to my coils if the quality of sound is not equal or similar to single coil of 0,32uH.
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Old 27th August 2012, 05:40 PM   #14
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a whole lot depends on things other than the coils.

the quality of the drivers is paramount.
then the enclosure, and its shape and construction.
finally the xover.

the xover must take into account the acoustic response of the drivers before during and after the intended xover frequency.

Frequently a 2nd order xover will not actually be that when the acoustic response of the driver + xover is measured.

One minor advantage of two coils is the option of changing the xover and/or reusing the coils later for something else.

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Old 19th January 2013, 11:45 AM   #15
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They will give less than the total nominal inductance if placed next to each other, no matter of orientation, about 10% less. I suspect this is caused by interaction of the magnetic fields. DCR will be higher than a larger coil of the same value due to difference in lenght of wire and core. Larger coils usually need a larger core, there is a formula for the most efficient way of winding to use the least amount of wire. If you place them at least 10cm away of each other, you will get the inductance as the nominal value of L1 + L2.
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Old 19th January 2013, 12:01 PM   #16
DF96 is offline DF96  England
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Quote:
Originally Posted by Mario Pankov
They will give less than the total nominal inductance if placed next to each other, no matter of orientation, about 10% less. I suspect this is caused by interaction of the magnetic fields.
Two coils wired in series and mounted near each other can have a total inductance which is more or less than the sum of their individual inductances. This is caused by their mutual inductance, which either adds or subtracts depending on winding sense and orientation.
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Old 19th January 2013, 01:15 PM   #17
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This link might give some insight into the comments that, if you use two coils, the placement will effect the result in a unpredictable manner.
Placement of coils in crossover networks
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Old 19th January 2013, 06:02 PM   #18
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Quote:
Originally Posted by prairieboy View Post
This link might give some insight into the comments that, if you use two coils, the placement will effect the result in a unpredictable manner.
Placement of coils in crossover networks
thanks, this is very helpful.
Regards,
V.
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Old 19th January 2013, 09:10 PM   #19
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Just did a quick check out of curiosity, two 0.56mH coils give 1.43mH ( +/- 3% stated accuracy for my RLC meter ) when on top of each other. DF96 made a good statement - depends on which end of the coils you connect, one side gives 1.05mH, when reversed its 1.18mH. Seems quite tricky if you don`t measure them.
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