You're allways right, this player you've done is complete useable, my problem was just a foolish mistake that the volumn of player(not N900) was set too high, make the phone play noise...
This is a great player, it seems IOS/android haven't such player can read 7z format as it. THX SZOPIN!!
I think 150Mhz which shows in XT should be 336 or higher