Quote:
Originally Posted by cmjones01
There is some evidence that not all cassette deck manufacturers actually used the same reference playback level for their Dolby decoding. I did some work on my Sony TC-K81, a somewhat high-end 3-head deck, and while searching the web for information on standard level tapes, found that Sony's 'Dolby' level wasn't quite the same as everyone else's - something like 235nWb/m compared with the standard 200nWb/m. I checked, and indeed the measurements specified in the service manual around the Dolby decoder chips seemed to reinforce this.
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Adding to the previous post, is it possible you came across the different standards for describing the same flux level? For example on an alignment tape I have here the same flux level is described as 295nWb/m (ANSI) and 320 nWb/m (DIN).
I'm not sure on this but I think cassette Dolby level at 400Hz is 185 nWb/m (ANSI) which is 200 nWb/m (DIN) which again is the same flux level.