The access to playing midi files and searching is that of the X1 from what I've seen so far. There is still the juke box mode which is where you search for the next song while playing the current song. If you are asking me if you can search for a song while playing the arranger, I am pretty sure it does that but I would have to check this out at my store today.
I have not installed the vocal harmonizer yet, but it is the same one as in the SD1 and X1.
The internal speakers sound great and there is a feature where you can boost or cut the bass and select the frequency you wish to boost or cut. There are 22 watts per side and what they did differently on the XD9 was to not use any wood within the speaker box so this helps to reduce the weight of this keyboard.
I would also like to mention that besides the stereo outputs, there is also a microphone output which takes the mic output to a pa without the effects.
George Kaye
Kaye's Music Scene
Reseda, California