I ran into sonmething odd the other day when I was playing Skyrim. My Dual-Wielding Thief was in Brtittleshin Pass. I was going to silently assasinate the Necromage and his Skeleton like I always do. Problem is, when I used my dagger (which was in the left hand; sword was in the right) on the Skeleton, my attack alerted the mage, leading to a much more difficult fight than I had anticipated. I'd never encountered this problem before, so I tried it again on some of the other skeletons in the next room; same result. The dagger killed it with it's x15 bonus, but the other Skeleton knew I was there.
I definitely only used the dagger when I attacked, so it's not like I accidentally alerted them with my sword. I scoured the web for info, but only found debates on whether Dual-Dagger or Sword-Dagger was the superior combat style. Has anyone else run into this? Is it a gltich? An oversight? Or is the silence of your duel-wield weapons determined by what you're holding in your main hand, regardless of what the off hand weapon is?
No I don't think that's it. Everything was fine until I hit the enemies with the dagger. Given the fact that daggers are silent it shouldn't even be an issue. I don't ever seem to have this problem when wielding dual daggers. (Though I'll admit, I also use my main hand when I do) My guess is that it's either the fact that the dagger is in my left hand, or it's the fact that I'm dual-wielding it with a sword.
I think I'll do some tests when I have the time and let you know what I find.
Also, a good tip is to assassinate the strongest foe first, and then defeat the weaker ones. In this case, the weaker foes are the skeletons, which are one of the weakest foes in Skyrim and are threat only while under special conditions.
So, I finally had time to test out my theory about the silence of weapons, and it turns out that my hunch was right. Get this: The silence of your weapons when dual-wielding is determined by the weapon you're holding in your RIGHT HAND. In other words, so long as you're wielding a dagger in your main hand, both of your weapons will be silent. This is why I thought it was so strange that the dagger in my left hand wasn't silent. Normally it is, but because I was wielding a sword in my right hand, it took the sound level of the sword.
On a funnier note, this also means that other one-handed weapons (swords, axes, maces) become silent as well so long as you have a dagger in your right hand.
So, I finally had time to test out my theory about the silence of weapons, and it turns out that my hunch was right...
Iv done some testing on PS3 and yes you are right. However its more complicated than you think, daggers are not 100% silent, an ancient dragon level 90 legendary dificulty will be alerted if you swing a dagger (even if you are invisible and have 100% muffle) if you don´t have high enough sneaking skill. With 100 sneak skill all one-handed weapons became silent.
It seems that Sneak skill, perks and enchantments do have impact in other things other than visual detection.
As an example I was unable to dual wield sneak attack the ancient dragon using shadow warrior perk/skill until i unlocked all sneak perks or wear a sneak enchanted equipment.