The Klipsch horns everyone hates are the K 401 metal mid horn, they are horrendous. How do I know, I have circa 1989 Klipschorn, had that horn stock. Thing rings like a bell, tried damping, got damped sound, gave up on that horn real quick. You've got to put a decent horn on a horn speaker to get anything close to proper timbre.
Most harsh/shrill sounding speakers (vintage)
Aside from the Yamaha NS-10M Studio Monitor, what are the worst sounding speakers that can make your ears bleed and provoke listening fatigue instantly even at a reasonably low volume. Speakers that are too bright, too snappy, too "honest", y'know, speakers that just sound like crap. The worst sounding speakers ever, if there is anything worst than the Yamaha NS-10.