Emerging digital audio applications for broadcast radio and multimedia systems are presenting new challenges such as the need to code mixed audio content, error robustness, higher audio bandwidth and the need to deliver high quality audio at low bit rates demanding a paradigm shift in the existing low bit rate speech coding techniques. This paper describes the continuation of our research concerning low bit rate speech coding and enhancements in the recently introduced bandwidth extension toolkit, Audio Bandwidth Extension Toolkit (ABET). Several new modes of operation have been introduced in the codec with the innovative use of perceptual coding tools. In addition, a new mode in ABET is added to improve the efficiency of the temporal shaping tool, Multi Band Temporal Amplitude Coding (MBTAC), by exploiting the time and frequency correlation in signals. The structure of the codec and its performance in these modes of operation are detailed. Audio demos and further information is available at http://www.atc-labs.com/lbr/
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