Bard Instrument issue?

[geniusi]

Hello all,

New player leveling a bard. I'm currently level 14 and have been following some guides, and they all say at lvl 8 when you get stringed instruments, that having one equipped will double the damage of my lvl 2 DoT. However when I equip a stringed instrument my DoTs do the same damage. I skilled up my strings skill to max for my level so I don't think that's the problem. When I equip a drum, my Selo's is noticeably faster. Any help would be greatly appreciated. Thanks!