I auditioned the D661a and D661s sets and I could not discern a difference between the two. I was expecting the silks to be a bit more tame, but they sounded just like the aluminums. I'm not saying you would experience the same and come to the same conclusion, I'm just providing my experience. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif