Open English Wordnet
(n)magnetostrictive speakera loudspeaker in which the magnet-and-coil assembly remains stationary; originated in sonar technology.“Magnetostrictive speaker drivers have some special advantages: they can provide greater force (with smaller excursions) than other technologies; low excursion can avoid distortions from large excursion as in other designs; the magnetizing coil is stationary and therefore more easily cooled; they are robust because delicate suspensions and voice coils are not required.”