There is a debate over whether the p/b distinction is based on voicing or aspiration, owing to the fact that the ostensively voiced stops are rather different from those of French or Hindi. Between voiced segments (especially vowels) they are voiced, but word-initially and finally they may be voiceless unaspirated stops and not voiced (this is speaker-dependent and also dependent on place). There is a complex set of factors that govern whether there will be vocal fold vibration. In "encouraged", the factors favoring devoicing are very high -- following a long period of obstruent closure, syllable final position, no following voiced segment. So it is quite likely that vocal fold vibration has been extinguished in this context. This is a non-neutralizing process, so even if vocal fold vibration has ceased in the final stop of "edged", it is still distinct from "etched". You would have to look at the phonetic details of a particular example recording to say what difference, if any, could be localized to [d] in this pair.