When usinginsitumeasurements to characterize the noise of a machine in other installations, the measurement space must meet certain qualifications, as outlined by Hübner. In cases where nearby walls and other reflective surfaces interfere, such surfaces may be given a temporary sound‐absorptive treatment. If the machine is symmetrical, measurements on an unobstructed side can be accepted as typical of both sides. Temporary barriers may be used to shield measuring microphones from the direct noise of other nearby noise sources which cannot be turned off. While some installations are hopelessly unsuitable for measurements of typical machine noise, such methods can often make an installation acceptable. Similar approaches can be applied to special‐purpose facilities used for noise measurements of machines and engines. An effective facility can be developed at minimum cost for making free‐field measurements above a reflecting plane to distances of at least 5 ft. A recently developed facility of this type in a vacant automotive collision shop was made by covering less than 50% of the hard walls and ceiling with panels of acoustic absorption. Nearly spherical speading (4–6 dB per distance doubling) was obtained out to 24 ft for frequencies above 250 Hz.