lawrecedent
500+ Head-Fier
- Joined
- Dec 8, 2013
- Posts
- 589
- Likes
- 70
That's exactly what the change table have said: 900 = glue; 900s = sonic weld.
I may be wrong but I took the sonic weld to be referring to how the back plates with UE logos were attached to the main body. I think the holder for the drivers is part Of the "new designed 4 unit divider tech". This could also account for the difference in sound quality perceived by some people in the old version as there would be minor differences in driver placement if they were just glued into the main body.