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<blockquote data-quote="Paul Johnson" data-source="post: 216937" data-attributes="member: 2643">I think some over-thinking and specification believing is happening. In the cassette days it was VERY common for people to record with Dolby B and turn it off for replay to get &#039;extra&#039; HF, with of course some extra hiss component. Dolby B just worked and people withy cheap machines had some switches to adjust for taste. Many machines had three options for replay EQ too - and the effects was mostly perceived as top end changes. Dolby C had a rough time, because Dolby was inextricably linked with &#039;noise reduction&#039;, as in removing hiss. Dolby C with the record processing and the reciprocal expansion didn&#039;t nice when settings were played with - as in turning the selector to Dolby B, or simply turning everything off. Dolby C encoding needs dealing with to restore dynamics to what they should be and the EQ curve. Oddly - back in those days we never used the specs like used here. The graph used above gives the impression that there was no bass, and loads of treble, but the scale on the blue graph makes it look far more than what is really was when you look at the curve and then the flat section. Dolby B applied variable gentle compression depending on the HF content - so don&#039;t take this as a standard compression method that can just be reversed. When you look at the curve of Dolby B off, Dolby B on and the impact of HF signals you can see the two tramlines have a gentle connection - it&#039;s not a straight line compression you can apply a straight line expansion to - like the HXpro thing. Dolby B replay with it off just makes a brighter sound - which you can leave in, or massage it out to taste. Unlike Dolby A there was no line-up or alignment - it just worked.</blockquote>

[QUOTE="Paul Johnson, post: 216937, member: 2643"] I think some over-thinking and specification believing is happening. In the cassette days it was VERY common for people to record with Dolby B and turn it off for replay to get 'extra' HF, with of course some extra hiss component. Dolby B just worked and people withy cheap machines had some switches to adjust for taste. Many machines had three options for replay EQ too - and the effects was mostly perceived as top end changes. Dolby C had a rough time, because Dolby was inextricably linked with 'noise reduction', as in removing hiss. Dolby C with the record processing and the reciprocal expansion didn't nice when settings were played with - as in turning the selector to Dolby B, or simply turning everything off. Dolby C encoding needs dealing with to restore dynamics to what they should be and the EQ curve. Oddly - back in those days we never used the specs like used here. The graph used above gives the impression that there was no bass, and loads of treble, but the scale on the blue graph makes it look far more than what is really was when you look at the curve and then the flat section. Dolby B applied variable gentle compression depending on the HF content - so don't take this as a standard compression method that can just be reversed. When you look at the curve of Dolby B off, Dolby B on and the impact of HF signals you can see the two tramlines have a gentle connection - it's not a straight line compression you can apply a straight line expansion to - like the HXpro thing. Dolby B replay with it off just makes a brighter sound - which you can leave in, or massage it out to taste. Unlike Dolby A there was no line-up or alignment - it just worked. [/QUOTE]

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