Custom Sub

Is your amp rated @4Ohms?

If so the manufacturer should give you specs for power at both 4 and 8.

HBomb

I would say VC parallel, drivers series.

Either way you look at it, you'll end up at 8ohm, right? I wish there was a good way to get you to 4ohm with all 4 vc's.

Cheers,
Russ

Straight From The Horses Mouth - Tempest White Paper:

3.2 Why dual voice coils?
After asking about the T/S parameters, the next most common question is ?why dual voice coils?? Most
high-end subwoofers have a single voice coil; so why dual?
Simply put, dual voice coils dramatically increase the flexibility of the driver. Most obviously, the total
impedance of the driver can be changed. As each voice coils is nominally 8W, one can run a single voice
coil and have a nominal 8 ohm woofer. But wiring the voice coils in parallel will yield a nominal 4W
woofer. And wiring the voice coils in series will yield a nominal 16W woofer. All in all, these
configurations allow easy use in low-voltage applications (4W woofer, for use in apps such as car audio), or
multiple driver systems (16W drivers allow one to parallel 2 to 4 drivers in a single system, and still
maintain an acceptable impedance without series connecting any drivers).
Note that the connection flexibility afforded by dual voice coils is equally great. For example, to use a
single channel of an amplifier (or a monoblock amplifier), one can connect the voice coils in parallel or
series (or just hook up a single voice coil) to meet the load requirements of the amplifier.
But, to use a stereo amp, one can connect a single voice coil to each channel. This allows the driver to act
as the ?summing? junction of a stereo signal, mechanically summing the stereo signals into a "mono"
driver. One does not need to electronically sum the channels together. This dramatically eases applications
where passive crossovers are used.
But the most important benefit for dual voice coils is flexibility for the T/S parameters. One can actually
?dial in? a desired Qts of the driver, by resistively loading one voice coil and actively driving the other.
This configuration, which we call Resistively Damped Operation (RDO), uses the second (undriven) voice
coil as an electromagnetic brake. In essence, the resistance across the second coil will determine how
strong the brake is. The smaller the resistance, the stronger the brake.
RDO affects the Qts of the driver by decreasing the Qms of the driver. The RDO brake acts to damp cone
motion, as if the suspension was considerably stiffer. However, as it?s an electromagnetic brake, the Fs is
NOT affected (as it would raise if the suspension components ? the surround and spider ? were stiffened).
This allows one to literally ?dial in? in a desired Qts by varying the Qms of the driver. In fact, a 250 W
5W potentiometer can be used to tune Tempest over a large range. For example, placing Tempest in an 113
liter box, and using the RDO configuration, one can dial in a system Qtc ranging from 0.65 to 1.2. This
allows tailoring the low-end response of the system to meet most musical/home theater reproduction needs.

No kidding it didn't answer your question - Russ already did that above and you thanked him for it.

I just thought maybe it would have been a helpful adjunct to your answer if you were considering altering the Qms of the driver for different applications and alignments.

Honestly, I can't answer that question.

Aside from obviously having the same final impedance either way, I have no idea if the sound quality would be different. I would definitely ask Adire this question - they have a good tech department.