sound volume/distance roll-off function (upside-down) reciprocated?

[splace]

although #124 has fixed the double dip, still not right...

when watching the volume change carefully, (with defaults) it jumps up to ~40% at outer edge then climbs quickly with a DECREASING gradient to 100% at inner edge.

what i think should be happening is; a jump to 1% (-40dB) then an INCREASING gradient to 100%.

the curve seems upside-down? and the outer limit is too high, but that could be explained by the curve form issue.

note: -40dB volume level (amplitude) == -20dB intensity.