I was wondering if anyone knew anything this ubiquitous tweeter which in the 70s seemed to be used on dozens of different companies' loudspeakers, from entry-level models to respectable "Buick-level" speakers. I've heard them many times and never thought they sounded *bad* and quite a few times I thought they sounded quite good, if a bit on the beamy side as far as dispersion is concerned. 1) what company designed it? 2) what was the phenolic ring - sometimes black, sometimes reddish brown - specifically used for? Why not plastic or some other material? 3) was KLH's cone tweeter the inspiration for it? I've seen these with small magnets weighing around only 3oz., and versions in better loudspeakers with heavy 8oz. magnets. I think some later models also included ferrofluid. Until a year ago or so, I saw this tweeter on the PartsExpress site and it was built by Pioneer. BTW: any thoughts on why cone tweeters fell out of favor? I realize domes are almost always better in most respects, but for 2-way systems their (relative) drawback is that their crossover frequency is usually much higher than the typical cone tweeter's xover point.* Did speaker system manufacturers finally decide that the advantages of a dome tweeter outweighed its problems in a 2-way system i.e. being crossed over at a higher frequency, say 2500kHz which could affect the system's midrange output? * I realize some domes had quite low xover points, like the one with the inverted dome made by Genesis in the late 70s/early 80s. I think it had a xover point at around 1500Hz or so.