The Collaborative International Dictionary of English v.0.48:

Euphonic \Eu*phon"ic\, Euphonical \Eu*phon"ic*al\, a.
   Pertaining to, or exhibiting, euphony; agreeable in sound;
   pleasing to the ear; euphonious; as, a euphonic expression;
   euphonical orthography.
   [1913 Webster]

WordNet (r) 3.0 (2006):

euphonical
    adj 1: of or relating to or characterized by euphony [syn:
           euphonic, euphonical]