ΔE 20.2, loose: different enough that you should pick on purpose. Kakophoni Purple is noticeably darker, much more saturated, warmer than Coven Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Kakophoni Purple is noticeably darker, much more saturated, warmer than Coven Purple.
The same difference applies the other way round: Coven Purple is noticeably lighter, much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Coven Purple on the colour wheel See Kakophoni Purple on the colour wheel
All matches: Coven Purple equivalents · Kakophoni Purple equivalents