A method for spectrally conditioning surface seismic data. The metal parts have fewer casting defects because the foundry shapes made with the binder are more resistant to erosion. The invention also relates to a method for manufacturing the device, a method for manufacturing the loop, a cavity filter and the casing. The capillary viscometer comprises: a capillary tube wound about a heated mandrel, a differential pressure transducer, and a reciprocating pump. Metal interconnections and high quality electrical components, such as inductors, transformers, capacitors, or resistors are formed on a layer of passivation, or on a thick layer of polymer over a passivation layer.