Both new headphones have a raft of new features to tempt the headphone-hungry, including proximity sensors (that will turn off your audio when they detect you've taken them off) and a one-touch transparency mode( so you can hear your surroundings more quickly).
Battery life has also been improved: the H8i have a claimed 30 hours of life, more than double that of the H8, while the H9i can get 18 hours from a single charge.
More after the break
There are a few new individual features to the headphones too: the H8i has physical buttons instead of the, ahem, "mesmerizing [sic] touch control" (their words, not ours) of the H9i.
The H9i also apparently have improved sound quality, thanks to a bass port that "ensures optimal and more powerful bass", and active noise-cancellation has been improved to better cancel human voices.
The two headphones will launch on the 25 January, in 'natural' and black colour schemes, at £350 for the H8i and £450 for the H9i.