An alternative to the classic reverberation‐time measurements for determination of sound absorption coefficients (ASTM C423) is the steady‐state method which measures the energy average sound pressure level of a reference source (of known sound power) with and without a sample in a reverberation room. In addition, sound power measurements in reverberant rooms require the use of a reference source to determine the room corrections. To successfully use these techniques, sound power must be known with great accuracy. With the advent of sophisticated sound intensity instrumentation, it becomes very easy to determine sound power in almost any type of space. In this paper, the authors report the use of sound intensity to test several reference sound sources in various environments, including reverberant, hemi‐anechoic, and semi‐diffuse, to determine the changes in measured sound output. In addition, the reference sources' emissions are compared with manufacturers' specifications based on techniques similar to S12.5, and intensity techniques. The differences among results for the sources/spaces/techniques will be discussed.