Diki, I am not convinced the sound quality does not measure up to the BK7m...The Bk5 sounds great to me..I have a pro player friend that played the BK5 and said it was a lot better sound than the Prelude...(I already knew that)....So other players can tell it is quality sound....

I have not played the two units side by side...so I can not swear there is no difference....

I did play the E-60 and G70 side by side, and yes there was a difference between common tones...as you mentioned, most likely sample size or converters..