
These diagrams show exactly what’s going in the Ring Thing while in RM (Ring Mod), UB (Upper Band) and LB (Lower Band) modes.
RM mode is the second diagram. In RM mode you will have both the upper and lower bands present, along with your original signal if mixed in using the BLEND knob. So if you have the Ring Thing to frequency shift your signal by 200 Hz and you put in 400 Hz, your Ring Mod output will be two signals one at 200 Hz and the other 600 Hz. Mix that with your dry signal and you have three frequencies present.
In UB mode (the third diagram), the lower band is eliminated so that the effect only produces the upper band frequency. In the above example you would only hear the 600 Hz signal plus your dry signal, no 200 Hz signal.
In LB mode (the last diagram), the upper band is eliminated so that the effect only produces the lower band frequency. In the above example you would hear only the 200 Hz signal plus your dry signal, no 600 Hz.