I had one of those autocorrelator units. I worked well enough with rock, but it messed with the sound of orchestral strings very badly.

I wouldn't be too hard on Dobly (sic), as analog tape hiss would be really worse in multitrack situations than any pumping or other artifacts from noise reduction. I do agree though, that listening carefully, and with some instruments such as solo piano, noise modulation becomes intrusive because of using noise reduction. But look on the bright side; one early proposal was to use Dolby ON TOP OF digital to get more S/N ratio!! Yikes!!!!