The role of nozzle configuration on rocket noise radiation is not well understood, particularly for multi-core vehicles where plume interactions may introduce azimuthal asymmetry. While tightly clustered engines are often assumed to radiate axisymmetrically, configurations with spaced nozzles may exhibit directionally dependent acoustic fields. This paper presents results from a measurement campaign conducted during the final Delta IV Heavy launch (NROL-70), supplemented by data from a previous launch (NROL-82), to investigate azimuthal variation in radiated noise. Measurements spanning a wide range of azimuthal angles show a consistent increase in sound pressure and sound power levels along the jet midplane relative to the jet plane. In sound pressure levels, differences of 5 dB are observed near the dominant spectral frequency (~30 Hz). In sound power, differences of ~2.5 dB are observed, particularly around the peak frequency, with smaller but persistent differences at higher frequencies. Strouhal number analysis indicates that the effective source length scale lies between the limits of fully independent and fully merged plumes, suggesting a partially merged interaction regime. These results provide field-scale evidence that multi-core rocket plumes do not behave as independent or fully merged sources but instead form partially coupled turbulent structures that produce directionally dependent acoustic radiation. The findings demonstrate that azimuthal asymmetry in large rocket noise is both angle and frequency dependent and should be considered in modeling of launch acoustics