pros and cons: beryllium vs ribbon tweeters in sound and emotions terms

I suspect each has unique properties and unless listening to a tweeter alone which is better depends almost totally on the smarts of the guy building the complete speaker and utilizing each to best effect.

Folded ribbon tweeters I’ve heard in recent years delivered a very relaxed and non fatiguing sound, almost to a fault if one expects recordings to have a bit of an edge to it from time to time.

Metal tweets in general historically seem to lean the other way in terms of their faults when mentioned but most I have heard in recent years in quality products have not struck me that way. Some like Focal may have been Beryllium. These were nicely etched in the highs but also very easy on the ears.

Low noise and distortion upstream to start with is always a good thing to help keep any good tweeter on your good side. For example I have Dynaudios with Esotar soft dome tweeter that delivers a lot of detail and energy to the top end but might drive one out of the room if noise and distortion upstream are not under control.

Also of course the dispersion patterns of a ribbon versus dome tweeter of any kind tend to be much different. That might be the most significant difference I would guess.

Just my observations.

If you want a 3D sound go with a 5 speaker setup, then use a good stereo upmix matrix, eg Pro Logic. You can then go with much much cheaper speakers. For layout, see the Grammy 5.1 guide.

I will think about this let you know in 2 months.