Key points are not available for this paper at this time.
Subjective ratings were obtained for four different speech waveform coders of varying complexity at each of three bit rates (24, 16, and 9.6 kb/s). atc (adaptive transform coding) is rated the highest and adpcm-f (adaptive differential pcm with a fixed predictor) the lowest, regardless of bit rate. Although there is large variability in the ratings due to different talkers and listeners, sbc (sub-band coding) is rated higher than adpcm-f and about equal to adpcm-v (adaptive differential pcm with a variable predictor) for most talkers and listeners. A weighted combination of two objective measures, one accounting for noise and the other for bandwidth effects, appears promising as a predictor of the subjective quality ratings.
Tribolet et al. (Thu,) studied this question.