Verity Parsifal or Magico V3 or Wilson Benesch ACT

Dhaan,
I do agree with you that carbon fiber is widely used in product design as a marketing tool. However in the case of speaker design, Wilson Benesch has demonstrated that it is not neccesary to form a "Univerity of Sound" :), but have a couple of engineers not afraid to wisely experiment with different materials and re-thinking speaker design development.
The WB's ACTs cabinet secret is, in my opinion, not the use of layers of carbon fiber, but the use of a cabinet made of a sandwich of composite materials with a core of high density foam. This ultra-light external structure instantly absorbs the energy generated from the drivers.
The combination of a very light external enclosure and a heavy metal internal matrix structure is a great approach to speaker cabinet design. The overall sound is superb.

Martin.

Dhaan,
Please, read my answer again. What I wrote before is that the WB's ACT cabinet uses a sandwich of composite materials w/ a high density foam core.
The ACT's cabinet is made of an internal layer of fiberglass, a high density foam (Last-a-foam) core material and an external layer of carbon fiber. What sounds-real-audio is trying to explain you, is that the carbon fiber will add rigidity to the enclosure while the high density foam will absorb unwanted resonances very fast. That is why you cannot use a thin metal sheet to replace the carbon fiber as you asked. The ACT cabinet is not just made of a thin rigid layer of carbon fiber, which would not absorb the sound, but layers of different materials. The overall cabinet thickness is around 13mm.

In my opinion, for such a small footprint the ACT's have, the unwanted resonances are very well controlled.

Thank you.