How does
Code:
00000110
00001111
00001111
00001111
00001111
00001111
00001111
look like a speaker?

How does the MCU know to start executing the program at $7000? I'm not a 68HC11 expert but I've done a bit of PIC programming and you need to put a jump at the start of program memory if that's not where the start of the program is. Obviously ignore this if the 68HC11 starts at $7000.

LDAA 0,X - OK, I guess this reads the 06 ff ff etc since X is initialised to #CC.
LDAB 0,Y - So what does this do? Y is initialised to #$40.