Its EQ optimation relative to the thin black ideal curves and optimized for CEA/CTA-2034 ANSI distance 2 meter farfield or more so bit different than optimazion for KH 80 where they optimize for on axis to name it a smooth nearfield monitor, if interested find them ideal curves attached below as txt-files. Directivity index curve and sound power plus listening window hang relative together in for example if you EQ listening window curve to same form as directivity curve tilted starboard 1,4dB/oct then sound power goes flat as a pancake and if listening window is EQed flat as a pancake then sound power goes a 2,8dB/oct tilted mirror of directivity curve.
Think its easyer to see the effect using JBL 305P MKII as in animated example below, whenever directivity index curve is below its ideal black curve then listening window is EQed to same form as directivity index curve tilted starboard 1,4dB/oct, but whenever directivity index curve is above its ideal black curve then listening window is EQed flat as a pancake
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