Don't know if this fix has been reported previously, but for people who haven't been able to get sound due to "Unusable voice playback device" error, (I think it may only be soundmax digital audio users, but I'm not sure), here's what I did to fix the problem.
1. Pop open the civilizationIV.ini file.
2. Find the "Enable voice over IP capture and playback" comment.
3. Set Enablevoice to false [0].
Sound should work the next time you start civIV up.
1. Pop open the civilizationIV.ini file.
2. Find the "Enable voice over IP capture and playback" comment.
3. Set Enablevoice to false [0].
Sound should work the next time you start civIV up.