Ambase rhymes with:
airbase, bouillabaise, broadbase, database, dbase, diabase, sybase, wheelbase, aerospace, airbase, airspace, anyplace, birthplace, boldface, bookcase, bouillabaise, briefcase, broadbase, bucase, cityplace, commonplace, cyberspace, database, dbase, diabase, diastase, dnase, electrospace, everyplace, fireplace, footrace, innerspace, interface, lactase, lovelace, maltase, marketplace, orthoclase, outpace, parcplace, plagioclase, polymerase, reiterates, scarface, shoelace, showcase, showplace, someplace, staircase, steelcase, steeplechase, streptokinase, suitcase, sybase, typeface, wheelbase, workplace
Ambase sounds like:
ambac, ambiguous, ambs, ambush, ambushes, amfac, amfesco, amoebas, amoebic, ampco, ampex, amphibious