Abstract: A new fast pitch-refining algorithm of MBE model, which is based on the feature of frequency domain error function around pitch, and a new scalable quantization scheme of spectral envelope magnitude, which is based on MBE-LPC model and Variable-Dimension Vector Quantization (VDVQ), are proposed. A 1.8 - 2.4 kbps scalable MBE coder is implemented with the new pitch-refining algorithm and the new quantization scheme. Experiment result shows that this MBE coder achieves the same synthesis quality as the original MBE-VDVQ coder in the same bit rate with much less computation and memory .