Frequency-difference beamforming is a sparse-array signal processing method that shifts the signal analysis to lower, out-of-band (difference) frequencies, provided that the difference frequency does not exceed the signal bandwidth. In an inhomogeneous environment with discrete scatterers, low-frequency fields may not be significantly affected, provided the scatterers are small relative to the signal wavelength. However, when the scatterer sizes are comparable to the signal wavelength, scattering effects are likely to be more significant. Previously, it was shown that frequency-difference beamforming can overcome some of the performance degradation from the high frequency scattering by shifting the processing to lower, out-of-band frequencies. In this case, the frequency-difference output was comparable to the output using a lower-frequency signal in the same environment. In this talk, theoretical fields that include scattering at the in-band frequencies are considered to predict the performance of the frequency-difference method. Furthermore, simulations and experiments in a 1.07-m-diameter water tank with a sparse array are used to determine the performance and robustness of the method in the presence of discrete high-contrast scatterers. Multiple realizations of randomly placed scatterers are combined to quantify performance statistics. [Sponsored by NAVSEA through the NEEC, and by ONR.]Frequency-difference beamforming is a sparse-array signal processing method that shifts the signal analysis to lower, out-of-band (difference) frequencies, provided that the difference frequency does not exceed the signal bandwidth. In an inhomogeneous environment with discrete scatterers, low-frequency fields may not be significantly affected, provided the scatterers are small relative to the signal wavelength. However, when the scatterer sizes are comparable to the signal wavelength, scattering effects are likely to be more significant. Previously, it was shown that frequency-difference beamforming can overcome some of the performance degradation from the high frequency scattering by shifting the processing to lower, out-of-band frequencies. In this case, the frequency-difference output was comparable to the output using a lower-frequency signal in the same environment. In this talk, theoretical fields that include scattering at the in-band frequencies are considered to predict the performance of the fr...