Tech That Flopped!

Every few months someone releases technology that seems to be revolutionary, but goes nowhere a couple of years later. Some tech gets acceptance and even imitation. Some goes wildly successful.

Ideas that are a huge success:

• Acoustic suspension
• Bass Reflex
• Soft dome tweeters

Some ideas, well, it's not so clear:

• Perfectly time aligned speakers ilke Thiel/Vandersteen
• ESL
• Line Arrays
• Plasma tweeters
• Transmission line
  

What tech have you seen come and go, was it worthwhile?

Best,

E