The amk2 Is one of the better hi frequency transducers available but RAAL ribbons are wonderful in there own right and 1 can design fine sounding loudspeaker with either transducer. Where design would be best if a amk2 is used a ribbon wouldn't be the best choice, same where a RAAL would work best that design wouldn't be so good for amk2. Hope this makes some sense ;) They are not inter changeable.