I've had both, and yes, that's the basic difference. The 1 is more boomy and the 1S is tighter in the low end. 1S has more in the mid highs while 1 has more of a noticeable V-shape.
Looking forward to seeing the reviews and first impressions of the VSD3 later this month.
Just out of my preference if the vsd3 does get to be V-shaped in some way, I'd prefer the vsd3s.
I bought the ostry KC06 which I loved but I'd welcome abit more bass impact and sub bass to it which the release of KC06A does justice to it. But wouldn't want the mids or highs to be compromised into V-shaped sounding. Now should I take the risk and preorder the vsd3 or get the vsd3s to be safe. Hmmm decisions decisions lel I have a local seller that has 1 more preorder available for vsd3s.