just comparing here:

XD3 1259 EUR
SD3 1599 EUR
SD5 1699 EUR
AUDYA 3777 EUR
AUDYA5 3550 EUR
AUDYA4 3111 EUR

so:
AUDYA 4 costs MORE than 2x the XD3 and about 2x the SD3

AUDYA5 (which is the "equivalent" of SD5)
costs MORE than 2x the SD5

questions:
are the AUDYA4/5 twice as good as their predecessors ???

is Ketron outpricing themselves from their competition?