I thought I would put it in "Document" so others won't have to hunt for it like I did...
VAB84 Description and Schematics
I found the English technical description and schematics for the VAB84 and it confirms the different method it uses over prior generations of "Elliptical Equalizers."
Nuemann VAB84 Block Diagram Showing Low Pass-Filtered "Side" Converted to "Mid" By Steering Into Left and Right Using Summation.
Nuemann VAB84 Description. The sliding filter is 6 dB per octave.
"Flank signal components are simultaneously transferred to the other channel."
Just what I had thought. Side gets converted to Mid via steering.
This reduces phase cancellation effects and provides a greater degree of mono compatibility.
Nuemann VAB84 Description. The sliding filter ranges from 0.1 to 1000 Hz.
The VAB84 moves the filter into the subsonic to get it out of the way when it is not needed.
Apparently, with a 6 dB per octave slope, Neumann engineers saw the need to get it out of the mid-band when not needed.
No re-matrixing of the Left and Right signal is necessary.
Nuemann VAB84 Description. Limiter Specifications.
Neumann VAB-84 pdf with schematics are here: http://www.waynekirkwood.com/images/pdf ... nglish.pdf
File courtesy of: http://audio.kubarth.com/
