@shadorne --
Highly rigid and light but poor internal damping.
Personally I don’t like the splashy sound of drivers of this type design (metal and highly rigid). They have great bandwidth that makes for impressive measured performance but I find the sound is "splashy" due to the way rigid materials vibrate naturally (like a bell vibrates and rings after an initial hit but a damped material like a pillow does not).
Splashy is a good term - as in when you splash the water it makes a lot of sound after the initial splash. Acoustically this means the driver imparts its own sound to the timbre whereas an internally damped cone material is much more inert - contributing much less coloration after the sound stops.
I prefer damped designs even though they tend to have a narrower bandwidth and can suffer from breakup and therefore require more careful design and larger more expensive drive motors. Damped cones sound much more natural and faithful to the original tone/timbre of recorded instruments even if they are not as linear on a speaker frequency plot.
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"Splashy" may indeed be a fitting term here. I’ve heard someone use the exact same term describing his impressions of the sound from a pair of JBL Project Everest DD66000, which uses beryllium diaphragms for both the midrange and tweeter. Some two weeks ago I had another listen to the JBL K2 S9900’s (last time before that I heard them was about 5 years ago), and this time around my personal reference for the last two years has been horn speakers using a composite diaphragm (apparently paper-based) for the midrange, and polyester ditto for the tweeter. I know there are many variables other than diaphragm materials here, but listening to the JBL’s this time around (which use coated magnesium diaphragms for the midrange) gave the impression of a slightly hollow, out-of-focus, and rather bleached/grey-ish midrange that further lacked presence and substance (we played a lot a different music, and the associating gear was top shelf Mark Levinson). I can honestly say that I much prefer not only the midrange but the overall sound of my own horn speakers, which are more refined, coherent and enveloping (bear in mind my speakers are augmented with a sub, but that doesn’t change the fundamental observation here) - and that at about a quarter of the price compared to the JBL’s (about a third incl. the sub). I was actually astounded to hear this, and it made me think about the importance of the diaphragm material - in addition to the material of the horn itself, and its geometry (and even further, of course, the x-over); looking at the JBL’s (both the K2’s and Everest’s) gives the impression of design aesthetics being a core parameter, so much indeed that it makes you wonder the nature of the midrange horn flares used (what’s even the horn geometry used here?), and how much they’re formed on the basis of a chosen (visual) design more than a consideration of the horn flare itself that would then dictate design aesthetics (i.e.: form follows function). I’m by no means an expert in horn geometry, not even close, but nevertheless that’s the sensation I’m getting here. I’m also wondering the benefit of the extended frequency span (upwards) using exotic metal as diaphragm material, as has been already suggested, when damping properties are negatively impacted - if at all truly a negative property in regards to sonic outcome. Sorry for the detour..
