subs and ohms

They're obviously not all identical subs, but if they are not same brand and size...wipe the slate clean and don't use this combination.  No use buying an amp or amps for a sub combo that won't behave.  Now, if they are same brand and size, all being equal except for coil configuration, and you insist on using all three of them, use separate amplifiers.  You want to be able to control the power so that all three subs perform the same (as much as is possible).

A two channel amp for the two single coils and a mono amp for the DVC.  You could also look into the 5 channel amps and you'll have a pair of channels left over for the front speakers.

But nevertheless, post model numbers of these beasts per forum guidelines for best advice.

Alright.  One last chance, hatch.  The model starts with "SWS...".  We can do some research and find a DVC 4 ohm sub, but no single 4 ohm.  Tell the forum what you are working with.  And be specific.  If you're mixing up various brands, step #1 of my previous post applies and we're done.

but if they are not same brand and size...wipe the slate clean and don't use this combination.  No use buying an amp or amps for a sub combo that won't behave. 

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.