Measurements of sound transmission loss made using nine different methods to estimate the effects of room absorption are reported. A single wall specimen was used in five different positions in the opening of a laboratory sound transmission loss test suite. Four different levels of room absorption were used. The conventional decay method is shown to work well in all cases, as does a method using a sound source with a known power to estimate the room absorption. A method using a sound‐pressure level near the source and the room average, the near–far method, did not work as well.