Synthesizers rhymes with:
exercisers, advertiser's, advertisers, advertisers', analyzers, appetizers, colonizers, exercisers, fertilizers, franchisers, ionizers, itemizers, merchandisers, mobilizers, organizers, rittereiser's, stabilizers, sterilizers, supervisors', sympathizers, tranquilizers
Synthesizers sounds like:
santa-croce, santa-cruz, snatchers, snodgrass