The innovative Zepler concept of spectral weighted energy density developed during the sonic boom research was later extended to include other short duration and transient community sounds and led to the development of a loudness level meter for the quantitative measurement of impulsive sounds. A wide variety of such short duration sounds was studied including the loudness, pitch, and pre/post-stimulatory effects of masking of pure tones, complex waveforms, noise bursts and pistol shots. Such researches made valuable contributions to the debates which were taking place over the acceptability, measurement and control of community noise nuisance.

His skills were also extended into the area of whole-body vibration and human vision where, although not fully conversant with the finer details of the subject, his penetrating and inquiring mind and inspirational and innovative grasp of the basic issues involved provided invaluable support and inspiration to his students.

Those seeking a single source reference to his numerous research and other contributions to ISVR are referred to E E Zepler et al, Journal of Sound and Vibration (1973) 28(3), 375-401; Human Response to Transportation Noise and Vibration.