Abstract: An acoustically pulsating burner assembly which includes an elongated outer tube, a fuel supply means located within the tube, and utilizes one or more integral axially adjustable Sondhauss thermoacoustic tubular elements to generate pulsations within the burner. The acoustic pulsations are generated inside the axially movable closed end tube element provided within the burner, and these vibrations promote more efficient combustion of the fuel so as to reduce undesired emissions in the combustion products. If desired, multiple thermoacoustic tubular elements of different lengths can be advantageously used to generate pulsations of different frequencies within the burner assembly. The burner assembly is located in a furnace windbox, and can be adapted for combusting gas, oil or particulate fuels such as coal.