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A concept for reducing combustion noise generated in gas turbine engines is presented. The suppressor concept involves perforating the engine casing either over or immediately downstream of the combustor (or both locations) and enclosing this area with resonator cavities. Experimental results were obtained for a number of flow and geometric variations using a 20-cm (8-in.)-diam single can-type research combustor. Several configurations, including the 10-cm (4-in.)-deep suppressor, gave 5-to 10-dB noise reduction in the 100-to 1000-Hz frequency range when located immediately downstream of the combustor. The test results indicate that it may be possible to reduce low-frequency combustion noise by liners considerably less deep than the conventional theories would predict. Applicability of the test results to full-scale engines is reviewed briefly.