Quick Sub Questions

If you have a dual voice coil sub, with two 4-ohm inputs, I understand you could wire both inputs in parallel for a single 2-ohm load to your amp channel. Or you could wire both inputs in series for a single 8-ohm load to your amp channel.

But for this particular application, I need a 4 ohm load to a single amp channel. Can I use just one of the inputs at 4ohm, and leave the other one disconnected? The sub is rated at 300Wrms continuous. Will it be just as loud using one 4-ohm input at 300Wrms, as if I was using both inputs at 2-ohm for each input and 150Wrms for each input?

(This is for those that know, not those that are guessing.)

No, you cannot wire just one voice coil. A DVC 4ohm speaker shows a 2ohm load or 8ohm load.

I just found this on the jlaudio site. You can do it, but it reduces your output by 3db and changes the characteristics significantly, so the enclosure size would need to be changed. Bottomline, not really an option, as Adam said.

"A common misconception with regard to dual voice coil speakers is the assumption that nothing changes if you power only one of the voice coils. With only one coil hooked up, a dual voice coil speaker will suffer a loss in reference efficiency of about 3dB (only half the coil windings are being energized) as well as a significant shift in its Thiele/Small parameters. This renders any enclosure calculations inaccurate unless you remeasure the speakers parameters with only one coil hooked up. Failure to account for the different parameters of a dual voice coil speaker with only one coil powered can result in very poor performance. "

http://mobile.jlaudio.com/support_pages.php?page_id=163