Ascendant's Atlas motors have an assymetric DVC configuration where the driven coil is 4 ohms and a secondary 2 ohm coil is used for resistively damped operation (em braking.)
My question is this:
If the specified Bl of the motor with the 4 ohm coil driven and the other left open is 11.7, what would it be with both coils driven in series (6 ohms total)?
Adire's Shiva white paper suggests one voice coil has half the Bl of both coils in series, at least when both coils are wound the same. Is it reasonable to assume that in the case of the atlas motor when both 4 and 2-ohm coils are driven, Bl would be 1.5 x that of the 4 ohm coil?
My question is this:
If the specified Bl of the motor with the 4 ohm coil driven and the other left open is 11.7, what would it be with both coils driven in series (6 ohms total)?
Adire's Shiva white paper suggests one voice coil has half the Bl of both coils in series, at least when both coils are wound the same. Is it reasonable to assume that in the case of the atlas motor when both 4 and 2-ohm coils are driven, Bl would be 1.5 x that of the 4 ohm coil?
The question is easily answered... if one knows the length of wire used to form the second voice coil. 😀
From Ascendant Audio's Chad Kuypers on their forum:
I posted this question over there, too, but no reply so far.
What he doesn't say is exactly how the T/S parameters change....
I posted this question over there, too, but no reply so far.
Bwbass, there is obviously a typo in that quote. In the 2nd paragraph, I believe it should be "The Atlas subwoofers actually work very well when wired in SERIES". This would give you the 6ohm impedance - anything in parallel would obviously drop at least below the main 4 ohm coil, even if you added resistance in series with the 2 ohm.
Yeah, I realized that but I didn't want to edit his quote. It's clear from the context what he meant to say.
Yes it's very reasonable to assume that BL will be 1.5x 11.7 so around 17.55.
Problem is that not only BL will change, I guess Qes will change too, so Qts will change.
Problem is that not only BL will change, I guess Qes will change too, so Qts will change.
Actually just today Chad Kuypers of Ascendant Audio responded:
That means Bl has gone up to just 13.9, or a 19% increase instead of a 50% one. It does explain the claim that the driver doesn't model much differently when wired like this, though. Perhaps the 2 ohm coil isn't "half of a 4 ohm coil" in all respects, or perhaps Bl is calculated in a non-linear way I don't understand, or both (most likely 🙂 ).
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