Speaker file created by the SPL Tracer, a speaker frequency response or impedance graph tracer application; contains speaker data, such as frequency and phase information necessary for drivers; similar to .ZMA files.

FRD files are used by Speaker Workshop, which enables users to design and test loudspeakers on Windows 95, 98, XP, and 2000 versions. To import the FRD file into Speaker Workshop select Resource → Import... or right-click the "Project Tree" and select Import..., navigate to your FRD file, and click Open. NOTE: The SPL Tracer and Audua Speaker Workshop programs are no longer available.