Subvolcanic rhymes with:
volcanic, volcanic, volcanic, mechanic, telemecanique, volcanic, annick, banick, banik, bannick, botanic, brannick, chovanec, danek, franek, galvanic, ganic, germanic, hispanic, hovanec, inorganic, janick, janicke, janik, koranic, magellanic, manic, manik, mazanec, mechanic, messianic, oceanic, organic, panek, panic, panik, romanik, satanic, stanek, stefanic, stefanik, szczepanik, telemecanique, titanic, transoceanic, tympanic, urbanik, volcanic, yanick, yanik, yannick
Subvolcanic sounds like:
splashing, splicing, subleasing