It is always nice to find low cost options isn't it. Seeing that the waveshape at the throat is not ideal I do expect that the dispersion in the horn is more than is really desirable, but I went on the principle that at the low end mostly the priciple longitudonal mode will be evident and that since the horn is short it the wave front would still have a considerable lateral componet due to throat scattering, something like it seems to work for Genelec