Vibrational response spectroscopy VRS is an attempt to adapt a relatively new technology to the study of the transition from deflagration to detonation DDT of high energy solid propellants. This technology is actually two technologies very similar in concept but differing greatly in their range and area of application. They are vibrational analysis the response of mechanical devices and structures to imposed mechanical vibrations, and acoustic emission AE analysis the recording and assessing of stress waves in solid structures. Vibrational analysis usually operates in the frequency range from DC to 10-30 kHz. In contrast AE is concerned with frequencies from hundreds of kilohertz to several megahertz. VRS was initially intended to span the range from 0-200 kHz, but a number of preliminary findings have led to a planned extension to higher frequencies.