1. An apparatus for noisy automatic speech recognition employing joint compensation of additive and convolutive distortions, comprising: an additive distortion factor estimator configured to estimate an additive distortion factor; an acoustic model compensator coupled to said additive distortion factor estimator and configured to use estimates of a convolutive distortion factor and said additive distortion factor to compensate acoustic models and recognize a current utterance; an utterance aligner coupled to said acoustic model compensator and configured to align said current utterance using recognition output; and a convolutive distortion factor estimator coupled to said utterance aligner and configured to estimate an updated convolutive distortion factor based on said current utterance using differential terms but disregarding log-spectral domain variance terms.