The answer to this thread's question surely must be that it's a matter of taste and preference. I have to confess to a certain prejudice against horns in general.
I'm a sound engineer, and having mixed a hundreds of concerts, the sound
of horns has never appealed to me. Guess it's that "shoutiness" and
edginess that even the best PA horns exhibit that turns me off. I like my sound a little warmer and more image-realistic than what I've perceived from horn-based systems, I guess. I listen to Magneplanars at home, and every time I sit down in front of them, I can sense an internal, inaudible "ahhhhh". They just suit my taste.
A couple years back, I had the fortunate opportunity to take part in a double-blind mono test between a Revel Salon2 (
very high-end, 6-way, traditional dome-tweeter design) and JBL M2 ("master reference" horn-based 2-way design) speaker. Both were free-standing behind a room-spanning scrim, and both were slid into place to exactly the same listening position alternately, as 10 samples of different kinds of music played via a high-end front end and amps. It was visually impossible to tell which was in place at any point, and levels were carefully matched. Both speakers are Harmon products voiced by Harmon.
Needless to say, both speakers sounded good, but there was a distinct difference in their character that gave away the M2s every time. There was about a dozen of us doing the listening, and we recorded our speaker preference for each sound sample. Post analysis showed that I preferred the Revel on every sample, and to my ears during the test, it was obvious which speaker was which. I just couldn't warm to that up-front, in-your-face shoutiness of what is admittedly maybe one of the best and accurate horns designs of all time. (The M2 is a lauded studio monitor speaker.) For what it's worth, only a couple of folks out of the dozen of us preferred the M2s on most of the samples.
What the test told me was
not that one speaker design was better than the other, but that they
were definitely distinctly different. Most folks preferred the domed tweeters over the horn in that test. That's a pretty small sample size, but it could be indicative of a much larger population's preferences. Maybe it answers the question that is the title of this thread. Maybe horns aren't more popular, simply because other types of high frequency transducers suit more folks' tastes a little better.
BTW, if you want an exhaustive thread of over 1700 posts on that blind test, it's on AVSForum here:
https://www.avsforum.com/forum/89-speakers/2907816-speaker-shootout-two-most-accurate-well-reviewed-...The testing was monitored and mentored by no less than Dr. Floyd Toole. A big shout out to John Schuermann and his crew for setting it all up and wrangling it all through the test. It was an altogether fantastic experience for these ol' ears.
