A low-frequency noise study was performed to investigate human response to the low-frequency content of aviation noise. High levels of noise can impact communities surrounding airports. Current predictive noise models and metrics may underestimate the impact of low-frequency noise (LFN) produced by aviation noise. Assessing the role of LFN in affecting human response will provide a better understanding of how this type of noise can impact communities. Indoor recordings of aircraft arrivals and departures at Washington Dulles International Airport (IAD) made in 2004 were used to assess subjective noise annoyance. These recordings variants having different levels of low-frequency noise were reproduced for subjects in the Gulfstream Supersonic Acoustic Signature Simulator II (SASS II); the subjects then rated the signatures for annoyance. Subjective judgments were statistically analyzed and compared between each signature and within each signature set against commonly used objective metrics. Results are shown that all other things being equal higher levels of low-frequency content in aircraft noise can result in increased annoyance in subjects and that the C-weighted sound exposure level correlated with this annoyance response with a coefficient of determination of 90%.