A method comprising: obtaining, using one or more processors, a frequency domain representation of a first set of samples from a plurality of target source level and spatial distributions in a plurality of frequency subbands; obtaining, using the one or more processors, a frequency domain representation of a second set of samples from a plurality of background level and spatial distributions in the plurality of frequency subbands; adding, using the one or more processors, the first and second sets of samples to create a combined set of samples; detecting, using the one or more processors, level and spatial parameters for each sample in the combined set of samples for each subband in the plurality of frequency subbands, wherein the spatial parameters include panning and a phase difference between two channels of a mixed audio signal; within each subband of the plurality of frequency subbands, weighting the detected level and spatial parameters by their respective level and spatial distributions for the target source and backgrounds; storing, using the one or more processors, the weighted level, spatial parameters and signal-to-noise ratio, SNR, within the plurality of frequency subbands for each sample in the combined set of samples in a table; and re-indexing, using the one or more processors, the table by the weighted level parameters, spatial parameters, and subband, such that the table includes a target percentile SNR of the weighted level and spatial parameters and subband, and that for a given input of quantized detected spatial and level parameters and subband, an estimated SNR associated with the quantized detected spatial and level parameters and subband is obtained from the table. obtaining, using one or more processors, a frequency domain representation of a first set of samples from a plurality of target source level and spatial distributions in a plurality of frequency subbands; obtaining, using the one or more processors, a frequency domain representation of a second set of samples from a plurality of background level and spatial distributions in the plurality of frequency subbands; adding, using the one or more processors, the first and second sets of samples to create a combined set of samples; detecting, using the one or more processors, level and spatial parameters for each sample in the combined set of samples for each subband in the plurality of frequency subbands, wherein the spatial parameters include panning and a phase difference between two channels of a mixed audio signal; within each subband of the plurality of frequency subbands, weighting the detected level and spatial parameters by their respective level and spatial distributions for the target source and backgrounds; storing, using the one or more processors, the weighted level, spatial parameters and signal-to-noise ratio, SNR, within the plurality of frequency subbands for each sample in the combined set of samples in a table; and re-indexing, using the one or more processors, the table by the weighted level parameters, spatial parameters, and subband, such that the table includes a target percentile SNR of the weighted level and spatial parameters and subband, and that for a given input of quantized detected spatial and level parameters and subband, an estimated SNR associated with the quantized detected spatial and level parameters and subband is obtained from the table.