Ladies & Gentlemen The additional criterion for voicing measure in MELP is peakiness. For r=1.4 the voicing in the first band is set 1 (strong voicing), for r=1.6 the voicing at second and third bands also set to 1. According to the classical paper "Selective Modeling of the LPC residual during unvoiced frames: White noise or pulse excitation" by D. Thomson & D. Prezas for gaussian noise r=sqrt(pi/2)=1.2533. You can easily check that for noise +1,-1,+1,-1,... r=sqrt(2)=1.41.... Thus it is not quite clear why MELP's developers chose this threshold for voiced/unvoiced discrimination which may classify ordinary noise as voiced what leads to buzziness. Does anybody know what was the reason to choose these thresholds in MELP? Thanks, Ilya Druker