From the Systems Neuroscience of Auditory Perception lab at Purdue University, a set of tools to analyze and interpret auditory steady-state responses, particularly the subcortical kind commonly known as frequency-following responses (FFRs). In particular, the package provides code for multitaper-analysis of spectra and phase locking along with complex-principal component analysis of phase-locking for multichannel FFRs. Although originally created to analyze steady-state electrophysiological responses, the generality of the spectral analysis and time-frequency analysis function allow them to be applied widely.