Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.