In passenger cars, the rear audio speakers are typically installed in a horizontal panel behind the rear passenger seat called the “parcel shelf”. Sound Answers was asked by an Automotive OEM to study the low-frequency vibrational characteristics of the parcel shelf and to develop an objective metric that could be used at the design stage to minimize loudspeaker-induced BSR noise. Data was acquired on six different vehicles so as to understand the variations in performance across the industry, and to aid in the setting of component-level targets for future production. Both operational (with loudspeaker) and artificial excitation data (with impact hammer) were acquired to characterize the modal and vibrational properties of the parcel shelf in each vehicle. The dynamic stiffness, natural frequencies, vibration mode shapes, and operational deflection shapes were determined from the measured data, and used to develop an objective metric for parcel shelf loudspeaker-induced BSR noise.