Far field is good. But that is NOT what anechoic measurements typically show. Due to size limitation and modes in the anechoic chamber, measurements are usually NOT in far field but somewhere between it, and near field. In contrast, the Klippel NFS measurements properly show the true far field sound radiation. The larger the speaker, the worse the typical anechoic measurement in this regard.
If you are performing far field measurements outdoor using gating, then you have signal to noise ratio, temperature and humidity variations.
True, but in the same vein, the smaller the speaker, the better anechoic chambers (and gating) are in this regard, and we've mostly been dealing with quite small speakers. I've seen many definitions of "far-field" in terms of wavefront integration. In his book, Dr Toole refers to a paper defining the farfield as starting at 3 to 10 times the largest dimension of a speaker, but clearly Harman is confident enough in 2m to trust that distance to measure and presumably design speakers like the 1.35m tall Salon2 - not anywhere near 3 to 10 times.
Personally, I've yet to see a single bookshelf speaker whose response meaningfully changes at 2M vs 1M within the resolution of my gated measurements. Still, with every speaker, I always repeat several measurements at 2m to see if my 1m measurements hold up. There's never been a difference, so I save the 1m data because of the better resolution. I expect towers would show a difference at that distance, but I have no plans to measure towers.
Anyway, at this point I'm just academically curious as to what caused that droop measuring at the stated acoustical center with the Klippel, since it uses gated measurements for the upper portion of the response. I highly doubt it's just an artifact of nearfield measurements as I'm pretty sure even at 1 foot only I wouldn't see that big of a treble drop. It's also a bit mysterious that the treble would then "fix itself" so dramatically once measured at the tweeter again, as the difference in position is definitely less than 20 degrees which was noted as looking flatter.
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