Auralization of numerically modeled impulse responses can be informative when assessing the geometric characteristics of a room. Wave-based acoustic modeling methods are suitable for approximating low frequency wave propagation. Subsequent auralizations are perceived unnaturally due to the limited bandwidth involved. The paper presents a post-processing framework for extending low-mid frequency band limited spatial room impulse responses (SRIR) to include higher frequency signal components without the use of geometric modeling methods. Acoustic parameters for extrapolated RIRs are compared with reference measurement data for existing venues and a Finite Difference Time Domain modeled SRIR is extrapolated to produce a natural sounding full-band SRIR signal. The method shows promising agreement particularly for large venues as the air absorption is more dominant than the boundary absorption at high frequencies.