I believe you can also use RS232 to change those settings, though it might be tedious. According to the manual I have these are for all Russound controllers:
Zone1 Bass Up
F0 00 00 7F 00 00 71 05 05 02 00 00 00 00 00 69 00 00 00 01 00 01 6D F7
Zone1 Bass Dn
F0 00 00 7F 00 00 71 05 05 02 00 00 00 00 00 6A 00 00 00 01 00 01 6E F7
Zone1 Treb Up
F0 00 00 7F 00 00 71 05 05 02 00 00 00 01 00 69 00 00 00 02 00 01 6F F7
Zone1 Treb Dn
F0 00 00 7F 00 00 71 05 05 02 00 00 00 01 00 6A 00 00 00 02 00 01 70 F7
Zone2 Bass Up
F0 00 00 7F 00 01 71 05 05 02 00 01 00 00 00 69 00 00 00 01 00 01 6F F7
Zone2 Bass Dn
F0 00 00 7F 00 01 71 05 05 02 00 01 00 00 00 6A 00 00 00 01 00 01 70 F7
Zone2 Treb Up
F0 00 00 7F 00 01 71 05 05 02 00 01 00 01 00 69 00 00 00 02 00 01 71 F7
Zone2 Treb Dn
F0 00 00 7F 00 01 71 05 05 02 00 01 00 01 00 6A 00 00 00 02 00 01 72 F7
Zone3 Bass Up
F0 00 00 7F 00 02 71 05 05 02 00 02 00 00 00 69 00 00 00 01 00 01 71 F7
Zone3 Bass Dn
F0 00 00 7F 00 02 71 05 05 02 00 02 00 00 00 6A 00 00 00 01 00 01 72 F7
Zone3 Treb Up
F0 00 00 7F 00 00 71 05 05 02 00 02 00 01 00 69 00 00 00 00 00 01 6F F7
Zone3 Treb Dn
F0 00 00 7F 00 02 71 05 05 02 00 02 00 01 00 6A 00 00 00 02 00 01 73 F7
Zone4 Bass Up
F0 00 00 7F 00 03 71 05 05 02 00 03 00 00 00 69 00 00 00 01 00 01 73 F7
Zone4 Bass Dn
F0 00 00 7F 00 03 71 05 05 02 00 03 00 00 00 6A 00 00 00 01 00 01 74 F7
Zone4 Treb Up
F0 00 00 7F 00 03 71 05 05 02 00 03 00 01 00 69 00 00 00 02 00 01 75 F7
Zone4 Treb Dn
F0 00 00 7F 00 03 71 05 05 02 00 03 00 01 00 6A 00 00 00 02 00 01 76 F7
Zone5 Bass Up
F0 00 00 7F 00 04 71 05 05 02 00 04 00 00 00 69 00 00 00 01 00 01 75 F7
Zone5 Bass Dn
F0 00 00 7F 00 04 71 05 05 02 00 04 00 00 00 6A 00 00 00 01 00 01 76 F7
Zone5 Treb Up
F0 00 00 7F 00 04 71 05 05 02 00 04 00 01 00 69 00 00 00 02 00 01 77 F7
Zone5 Treb Dn
F0 00 00 7F 00 04 71 05 05 02 00 04 00 01 00 6A 00 00 00 02 00 01 78 F7
Zone6 Bass Up
F0 00 00 7F 00 05 71 05 05 02 00 05 00 00 00 69 00 00 00 01 00 01 77 F7
Zone6 Bass Dn
F0 00 00 7F 00 05 71 05 05 02 00 05 00 00 00 6A 00 00 00 01 00 01 78 F7
Zone6 Treb Up
F0 00 00 7F 00 05 71 05 05 02 00 05 00 01 00 69 00 00 00 02 00 01 79 F7
Zone6 Treb Dn
F0 00 00 7F 00 05 71 05 05 02 00 05 00 01 00 6A 00 00 00 02 00 01 7A F7