A method of filtering noise and restoring attenuated spectral components in acoustic signals generated by drilling equipment, the method being characterized by the steps of: performing, for each record of one or more acoustic records comprising a plurality of raw data samples in frequency domain format, the step of: dynamically filtering each of the plurality of raw data samples in frequency domain format for the respective record to remove or attenuate background noise contained in the plurality of raw data samples to produce a corresponding plurality of cleaned data samples, the plurality raw data samples in frequency domain format produced from a corresponding plurality of acoustic signal samples for the respective record, transformed from time domain format to frequency domain format, each of the raw data samples comprising sample-specific acoustic signal data and sample-specific background noise, the sample-specific background noise of each separate one of the plurality of raw data samples being removed or attenuated by a record-specific dynamic filter applied to each of the plurality of raw data samples to produce the corresponding plurality of cleaned data samples, the record-specific dynamic filter at least partially being defined by a dynamic amplitude noise cutoff ( A th), the dynamic amplitude noise cutoff ( A th) being defined by a sum or product of a record-specific base noise percentile ( P b) and a record-specific value of a threshold parameter ( C th), the record-specific base noise percentile ( P b) defining an amplitude percentile determined for a record-specific specific frequency range for the record, the record-specific specific frequency range comprising a subset of a frequency range of the record determined to correspond to noise, where data for a sample having an amplitude below an amplitude corresponding to the amplitude percentile is considered to be noise, and the record-specific base noise percentile ( P b) being the same for each of the plurality of raw data samples for the respective record, the threshold parameter value ( C th) being a constant that is the same for each of the plurality of raw data samples for the respective record, and the dynamic amplitude noise cutoff ( A th) being separately applied to each separate raw data sample of the plurality of raw data samples for the respective record. the plurality raw data samples in frequency domain format produced from a corresponding plurality of acoustic signal samples for the respective record, transformed from time domain format to frequency domain format, each of the raw data samples comprising sample-specific acoustic signal data and sample-specific background noise, the sample-specific background noise of each separate one of the plurality of raw data samples being removed or attenuated by a record-specific dynamic filter applied to each of the plurality of raw data samples to produce the corresponding plurality of cleaned data samples, the record-specific dynamic filter at least partially being defined by a dynamic amplitude noise cutoff ( A th), the dynamic amplitude noise cutoff ( A th) being defined by a sum or product of a record-specific base noise percentile ( P b) and a record-specific value of a threshold parameter ( C th), the record-specific base noise percentile ( P b) defining an amplitude percentile determined for a record-specific specific frequency range for the record, the record-specific specific frequency range comprising a subset of a frequency range of the record determined to correspond to noise, where data for a sample having an amplitude below an amplitude corresponding to the amplitude percentile is considered to be noise, and the record-specific base noise percentile ( P b) being the same for each of the plurality of raw data samples for the respective record, the threshold parameter value ( C th) being a constant that is the same for each of the plurality of raw data samples for the respective record, and the dynamic amplitude noise cutoff ( A th) being separately applied to each separate raw data sample of the plurality of raw data samples for the respective record.