Bass is 0-100hz, treble is 10000hz+. These are standard ISO frequencies for bass/treble.
Bass and Treble are independent from Eq knobs, it's 2 extra bands. Also they can't/don't reduce level of their frequencies - zero (left corner position) means no change of sound at all.
There are 10 equ bands + 2 tone bands = 12 in total. This is nicely processed on NEON enabled cpus - 4 samples for 2 bands with one cpu instruction/cycle, 32 bit internal processing.