Dual voice coils

[Opie]

For a subwoofer with dual 2 ohm voice coils, what will the efficency be with the coils wired in series for a 4 ohm load?

Thanks,

Opie

 

[daatkins]

Parallel connected voice coils increase efficiency 3dB and sensitivity 6dB over using a single voice coil.

Series connected voice coils increase efficiency 3dB and does not alter sensitivity over using a single voice coil.

Have a look at section 3.5 of the Shiva white paper:
http://www.adireaudio.com/Files/ShivaWhitePaper-V2.PDF

It includes a table of how different configurations of voice coil and drivers add up.

Nice one,
David.