These Recommended Practices define terms associated with loudspeakers and their testing, recommend various methods of testing, and indicate preferred methods of presenting information regarding their characteristics. Specific information is presented in Sections 2-7. Discussions of a more qualitative nature are given in Sections 8 and 9. In these Practices, the tests recommended involve physical, steady-state measurements only. Work has been and is now being done on transient measurements of loudspeaker performance, but experience with these methods is still not sufficiently widespread to warrant their inclusion. While the physical data which can be obtained as detailed in Sections 4-9, inclusive, are a helpful guide in designing and in selecting a loudspeaker for a certain purpose, they are not a complete guarantee that the subjective performance will be satisfactory. Wherever it is possible, the quality of reproduction should be checked by means of listening tests such as those described in the literature.1