An example is shown of the steps in the design of the structure for noise control of a jet engine test cell from the determination of the design goal to the final acoustic treatment of the cell. An arbitrary design goal was set from a previous survey of city noise. With the expected octave band levels at a distance of 3000 feet, for 10 jet engines with afterburners the quieting necessary is 50 and 55 db, respectively, in the 150–300 and the 300–600 cps bands, these two bands being the most difficult to control. An analysis of the required volume and dependent cost of the structure is given as the function of the amount of quieting needed, the quantity of heated gases exhausted, the temperature of the gases, and the velocity of flow permitted. Two unconventional but economical systems of noise control, (1) a series of acoustically treated plenums and (2) a series of acoustical lined 180‐degree turns, are recommended. Design equations and confirming data from model studies are presented.