You can't just make a speaker whatever impedance you want it to be.
A single voice coil speaker is what it is. There's no trick to make it something else.
With a dual voice coil speaker the coils can be connected in either series or parallel resulting in different impedances. For example, a dual 2 ohm voice coil speaker can be wired with the coils in series, making it 4 ohms, or in parallel making it 1 ohm. Likewise, a dual 4 ohm voice coil can be wired for 2 or 8 ohms.
Additionally - multiple single or dual voice coil speakers can be connected in series, parallel, or a combination of the two.
A pair of svc 4's can be wired for 2 or 8 (just like one dvc 4)
A pair of dvc 4's can be wired for 1, 4 or 16.
A pair of dvc 2's can be wired for 1/2, 2, or 8.
So for 1 speaker to net 1 ohm you would either need a single 1 ohm voice coil, which I don't think I've ever seen, or a dual 2 ohm voice coil wired parallel.
There are also some quad voice coil subwoofers out there, but they're very rare.
Answers & Comments
Verified answer
You can't just make a speaker whatever impedance you want it to be.
A single voice coil speaker is what it is. There's no trick to make it something else.
With a dual voice coil speaker the coils can be connected in either series or parallel resulting in different impedances. For example, a dual 2 ohm voice coil speaker can be wired with the coils in series, making it 4 ohms, or in parallel making it 1 ohm. Likewise, a dual 4 ohm voice coil can be wired for 2 or 8 ohms.
Additionally - multiple single or dual voice coil speakers can be connected in series, parallel, or a combination of the two.
A pair of svc 4's can be wired for 2 or 8 (just like one dvc 4)
A pair of dvc 4's can be wired for 1, 4 or 16.
A pair of dvc 2's can be wired for 1/2, 2, or 8.
So for 1 speaker to net 1 ohm you would either need a single 1 ohm voice coil, which I don't think I've ever seen, or a dual 2 ohm voice coil wired parallel.
There are also some quad voice coil subwoofers out there, but they're very rare.
check out rockford fosgate.com click on support and go to woofer wiring wizard