I think you are both
(Im talking brownee & carbine earlier - chopper jumped in there) partly correct ... heres how I see it.
The pulleys on each side back to fixed central point on the front lines does just as cabrinah/brownee says in doubling the distance of depower/powerup for any given length of bar travel - pretty basic really & also explains the reports of harder work for any length of bar movement.
But the cabrinah 2/1 bar must also have some of the pulley bar effect. When turning the Xbow you are effectively pulling twice as much toward your inside turning edge & releasing twice as much on your outside turning edge for any given tilt of the bar. The double pulley set-up may not be the equivalent of a single pulley bar
but the same principle is being applied.
Another point I havent heard anyone mention or talk about is the effect of having the fixed central point off the pulleys at the
top of the trim strap. This adds in another new control variation from the standard line 4 line set-up. Trimming out with 2 pulleys reduces backline length as well as extending the front line length. Again double the variation in the AofA for any given distance the trim strap is adjusted.
I would have thought that all standard 4 line LEIs would already have been using the maximum workable AofA variation with existing trim strap set-ups
Or is it that a flatter kite provides a greater workable AofA range.
I dunno - getting way too technical for my little brain
