About DRA Laboratories

Current owner Doug Rife founded DRA Laboratories in 1986. Developing MLSSA involved much more than software and hardware design. A large part of the work involved creating and refining algorithms as well as doing in-depth analysis of MLS (maximum-length sequence) methods regarding audio and acoustics measurements. This theoretical work resulted in two published papers. The first titled "Transfer-Function Measurement with Maximum-Length Sequences" was published in the Journal of the Audio Engineering Society (JAES), Vol. 37, No. 6, in the June 1989 issue. This paper provides a comprehensive analysis of MLS measurement methods and won an AES Publications award in 1992. A second paper titled "Modulation Transfer Function Measurement with Maximum-Length Sequences" was published in the JAES, Vol. 40, No. 10, in the October 1992 issue. This paper presents and proves an original theorem that makes possible the fast and highly accurate speech intelligibility measurement capabilities of MLSSA. As a result of his theoretical work the Audio Engineering Society awarded Mr. Rife an AES Fellowship in 1993. Mr. Rife is also a member of the Acoustical Society of America and has presented oral papers about MLS measurements at various times under its auspices.