A method includes filtering, at a speech encoder, an audio signal into a first group of sub-bands within a first frequency range and a second group of sub-bands within a second frequency range. The method also includes generating a harmonically extended signal based on the first group of sub-bands. The method further includes generating a third group of sub-bands based, at least in part, on the harmonically extended signal. The third group of sub-bands corresponds to the second group of sub-bands. The method also includes determining a first adjustment parameter for a first sub-band in the third group of sub-bands or a second adjustment parameter for a second sub-band in the third group of sub-bands. The first adjustment parameter is based on a metric of a first sub-band in the second group of sub-bands, and the second adjustment parameter is based on a metric of a second sub-band in the second group of sub-bands.