1. A system comprising: a computer-readable memory storing executable instructions; and one or more physical computer processors in communication with the computer-readable memory, wherein the one or more physical computer processors are programmed by the executable instructions to: receive a first audio signal comprising: first audio data corresponding to a user utterance; and second audio data corresponding to reverberation of the utterance; determine a dynamic range of sound intensity of the first audio signal as a difference in sound intensity between a first portion of the first audio signal corresponding to a time at which the user utterance has ended and a second portion of the first audio signal corresponding to background noise; determine that the dynamic range exceeds a dynamic range threshold; determine a maximum autocorrelation for the first audio signal by determining the maximum value of a first function modeling a correlation of the first audio data with the second audio data; select a local maximum autocorrelation value for each of a plurality of groups of values of the first function, wherein each of the plurality of groups of values of the first function comprises consecutive values associated with a decrease from the maximum autocorrelation; determine a second function approximating a decrease in sound intensity in the first audio signal after the time at which the user utterance has ended by approximating the local maximum autocorrelation values for the plurality of groups of values with respect to time; determine a current reverberation time by computing a value of the second function corresponding to a threshold decrease in sound intensity; determine an average reverberation time by averaging the current reverberation time and a previous reverberation time; determine that the average reverberation time exceeds a reverberation time threshold; obtain a second audio signal; and generate a de-reverberated audio signal by processing the second audio signal using the average reverberation time to reduce reverberation in the second audio signal.