@kota1 @thespeakerdude
When anything is put in front of a speaker the wave is deflected somehow, when you put something like window louvers or a horn to guide high frequencies the wave is deflected. Many have mentioned "wave guides" and acoustic lenses focusing the sound, well I thought that was a fad 30 years ago because of course waves interact poorly when they are changed and mingled. I understand the kind of filter some speakers put over drivers that look like a grill to break up the waves in a particular way but focusing the wave is never a good thing, we called it near field reflections back when all those speakers were tossed away. Are they back? Has someone discovered how to make waves interact and keep the amplitudes in tact after the focusing? Even the grill on my own 9hs has a high tech symmetrical design to defocus the beryllium tweeters and midrange from sounding to harsh that is done on purpose to smooth (distort) the high frequency I understand that but if the acoustic lens is a guide that focuses the wave there aren't there inevitable problems.
I always think of microphones when I think of speakers, once I was doing sound for a concert with Wynton Marsalis, I was a big fan and very excited to work with him. He told me to put a Sennheiser 421(a large diaphragm dynamic mic) down stage and that's all he said his trio would play into it, they would mix themselves as they got closer and farther from the microphone. Just like Edison did on the first recordings ever. Well as you probably guessed the sound was great. The sound was so good it left an indelible impression about how important phasing was I never forgot.