Sound card to power miltary headset.

Hi all. I have a headset that has 2 18 ohm speakers wired in parallel.
I am trying to use it with a standard sound card and wondered what i need to do to get it working. The person here before me was using a line to voice coil (A-3837) which works, but is very very hard to hear. Any suggestions would be appreciated. Thanks!

Well i ended up hacking a computer speaker set for the amplifier. Works pretty good now.