Abstract: A gas turbine engine test cell has a turbine detuner capable of recovering kinetic energy from exhaust gases emitted by a gas turbine engine while also detuning the exhaust flow to reduce unwanted infrasound. The gas turbine engine test cell includes a test cell building, a thrust frame for mounting the gas turbine engine, and the turbine detuner disposed downstream of the thrust frame for extracting energy from the exhaust gases of the gas turbine engine when in operation. The turbine detuner has an inlet for receiving the exhaust gases, a kinetic energy recovery mechanism (e.g. stator and rotor) for converting the kinetic energy of the exhaust gases into rotary power, and an outlet through which de-energized exhaust gases are emitted after being de-energized by the kinetic energy recovery mechanism. By eliminating the augmentor, the test cell is more compact. The turbine detuner not only reduces infrasound but also recovers otherwise wasted energy.