A bulk acoustic resonator assembly and methods for fabricated the resonator assembly is provided. The resonator includes a cavity on a first surface of a substrate, with a sheet of low acoustic loss material suspended over the cavity. The sheet of low acoustic loss material is configured such that an associated fundamental frequency of the sheet of low acoustic loss material is a function of a length of the sheet of low acoustic loss material in a direction parallel to the first surface of the substrate. A transducer includes an electromechanical layer on the sheet of low acoustic loss material and a patterned conductive material formed on the electromechanical material. The transducer is configured to induce vibrations in the low acoustic loss material upon application of an electrical signal to the conductive pattern.