With an uncorrected mass corner around 433Hz, this is way too high for me, so I guess it's a 'different strokes for different folks' situation.FR tech forum gallery?
Anyway, if you plot out what I posted you'll see that until you get near the mouth of the full size horn, which you wouldn't since the cutoff would be at a much higher frequency, the expansion is conical enough that I'd bet dollars to donuts you couldn't hear the difference outdoors, much less in a typical room.
GM