Abstract: A muffler (50,50') for use in conjunction with a plurality of aspirators during the production of multifilament, synthetic yarn is provided. The exhaust tubes (32) of the aspirators are clustered for discharge by and through the muffler (50,50') which reduces audible noise collectively emitted at the exit ends of the exhaust tubes (32) by as much as 16 .DELTA. dB(A) and more. The noise is reduced and any waste yarn transported through the use of a plurality of perforated tubes (59,59'), resonant cavities (61,61'), and sound absorbing material (62,62').

Abstract: A muffler for use in conjunction with a high intensity, low frequency noise-propagating open pipeline is disclosed. The muffler features an acoustically lined expansion chamber in tandem with a reasonator chamber. The length of the expansion chamber is approximately 25 percent of the wavelength to be attenuated. An exit tube, which passes through the resonator chamber to lead from the expansion chamber to the muffler outlet, is partially perforated with the perforations being restricted to at most the 50 percent of the exit tube closer to the muffler outlet. Audible noise which is emitted by the open pipeline is reduced by up to 30 dB and 11 .DELTA. dB(A) and brought to within acceptable levels.