Is it possible to wire a dvc 4 ohm sub with a dvc 2 ohm sub to 1 amplifier at 2ohms?

NO

but CCA won't let me put in a 2 letter answer

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You can get close......series your d4 coils to 8ohm, series your d2 coils to 4ohm then parallel the two together for a 2.666ohm load.

Don't do it, you will get wildly different power to the different impedence subs.

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I like my gear to be loud and clear.

Don't listen to Trebor.

Gee thanks, perhaps you should show me where my math is wrong.
R=Resistance. (R1×R2)/(R1+R2)=R3

And to address the power difference, yes it is true that one speaker will get more power than the other, for the safety of the subs and from interfering with each other mechanically, keep them in separate enclosures. To your ears I doubt you will notice much if any difference. Even if one speaker was getting 1k watts and the other 500watts, we're only talking about 3db.

It's not practical. If you use separate enclosures you'll have one sub getting more power than the other and the one will simply drown out the other. Both will be playing the same frequencies, only one will be louder so it will drown the other out. You'd be better off just wiring up the dual 4 ohm sub to 2 ohms so long as it can handle the power.

How much power do you think it would take for one sub to ''drown out'' another sub playing the exact same frequencies?

If each speaker sounds good in it's own enclosure then there's no reason they won't sound good together just because one is getting a little more power. I've already described how minimal the volume difference is between 500 and 1000watts. It's not the most prefered situation but that doesn't mean it can't work.

3db is minimal? I don't think so. Playing the same frequencies is not practical. As I said running one is a better option because it gets more power. Using the two different sub enclosures would be beneficial if you bandpassed them (i.e. you have sub 1 play a certain range, sub 2 plays a different range). There is only one amp so that isn't possible. The best solution is to use the dual 4 ohm sub (so long as it can handle the amount of power). I will admit that you can run both subs at 2 ohms, but it is not the best way to do it.

What isn't practical about two subs playing sub frequencies instead of one and why would you bandpass speakers separately that are designed to play the same portion of that audio spectrum?

The OP simply wants to know if its possible to get a 2ohm load using two subs with different impedances, my answer is he can get close and to make sure each sub is kept in a seperate appropriately sized enclosure. What's so hard to understand about this? From there it's up to the OP to decide whether I know what I'm talking about or not.