Not to say that my reviews are always perfect (I get things wrong too), but there is definitely a few misunderstandings about horn design in that article. The problem with bad horn design isn't that it amplifies bad tweeters so much as it creates a lot of diffraction and also doesn't control directivity very well. A good waveguide will control directivity over a very wide frequency band and also avoids diffraction effects. That is really hard to do. Some of the very few waveguides that do are the Image Control Waveguide from JBL, the Oblate Spheriod waveguide from Earl Geddes, and the SEOS waveguides developed for the DIY Sound group. They all involve very complex mathematical modeling. The Hybrid tractrix waveguide by Klipsch seems to be decent, although we do see some diffraction effects when you know what to look for. I pretty much assume that any speaker's waveguide is flawed until I see hard proof of their performance. It's not common that horns are executed perfectly. See
this chapter in Geddes' Transducers book to see how complex waveguide design can get. A lot of horn loudspeaker manufacturers don't go through that much effort or have that much expertise on hand. The bi-radial horns used by the Studio 500 series is probably not as sophisticated as some of the above mentioned designs.
That review states that the waveguide controls the tweeter down to 1 kHz, but the crossover point is 1.5 kHz. The reviewer also states that the woofer is somehow partially horn-loaded "probably to improve its reach rather than to augment its sensitivity," but that is just not true. Any waveguide that would even partially augment its sensitivity would have to be gigantic. The review also says that the Studio 530 somehow has a low sensitivity (which they mis-state as 86dB for 1w at 1m when it is spec'd at 86dB for 2.83v at 1m; those specs are significantly different). The sensitivity is about average, maybe even a tad above average, for that kind of bookshelf speaker. They say that the Klipsch RB-51 is four times better at 92dB, to which I response BWA-HAHAHA! Never take Klipsch's stated sensitivity specs at face value. It's doubtful that the Klipsch speakers are any more sensitive at all.
