Byte 189 starts 20 sets of 2 bytes which are literal encoding of the band in hz. So for 50hz it's octal 62 in byte 189 and 0 in byte 190. For 18khz it's 120, 106. It tops out at 18khz. I guess what's left are:
-figure out how to toggle 2-4 channel mode, i need to reboot the player
-figure out the parametric equation.