For speakers:
1. Improved woofer (new HP woofer in some models as standard)
2. Improved mid-woofers
3. New tweeter
4. Cast baskets
5. New surround and voice coil adhesives (part of 1 and 2)
6. New cross-overs (upgraded parts, new filters, improved component layout, improved PCB layout, heavier traces). This partly came from an improved understanding of the Family of Curves and partly from an improved understanding of component and PCB quality on the system performance.
7. Improved cross-over mounting within the cabinet
8. New feet and mounting of feet
9. Improved way of mounting all drivers rather than screwing them into MDF
10. I suspect a new MDF chemistry
11. New vinyl formulation and now wood as standard
12. Improved cabinet bracing
13. More cabinet stuffing
14. Improved mid-woofer chamber
All the above has resulted in a different and more realistic soundstage, improved imaging and blackness between the images, improved fidelity throughout the entire frequency range including less distorted lows, snappy mid-bass, more dispersive mids, dreamy highs, improved micro and macro dynamics.
The sealed subs are completely different beasts than the old subs in so many good ways.
So glad I ditched my v2. Anyone who worked on the v4 ought to be very proud.
