Effect adding apparatus, method, and electronic musical instrument

A method performed by a computer of an effect adding apparatus including at least one processor and a plurality of first operation elements operable by a user to change parameters assigned to the respective first operation elements, the method being performed under control of the at least one processor, and the method comprising:

• selecting a parameter to be assigned to each of the first operation elements, from among a plurality of parameters corresponding to designated effects, the designated effects being effects designated from among plural selectable effects;
• when a plurality of the plural selectable effects including a first effect and other effects are to be used in combination as the designated effects, changing the parameters to be assigned to the plurality of first operation elements from among the plurality of parameters corresponding to the first effect in response to a change in the other effects to be combined with the first effect;
• and
• adding the designated effects to a musical sound generated by a sound source.