Actually you can build a cabinet out of very thick mdf and the cabinet will be very innert, companies such as Avalon and Usher make suberb cabinets out of mdf. In the case of Usher the cabinets walls around 2 inches thick and a pair of BE 20 weigh almost 300 lbs.
Aluminum can make an excellent cabinet, it is monotonic and will ring unless it is damped.
The sound of a speaker is just that we have heard very life like recreations of the studio from ATC loudspeakers,
The only person who knows exactly what sosmething sound like was the person in the room who heard the original performer.
As Itzak said it is a matter of personal taste and what you like.
We sell Kef, Dali, ATC, Quad, Elac, Paradigm monitors. These range in price for $2,500.00-$8,000.00 they all can sound wonderful and each loudspeaker has it strengths and weaknesses:
The Elac Adante hits hard with a lot of bass, good treble detail a bti more forward then the ATC SCM 11 with way more bass.
The ATC SCM 19 sounds smoother and more refinded then the Elac with a bit less coloration and a huge soundstage
The Kef Reference One has more upper ocative detail then the ATC through a bigger soundstage and have greater bass, with a clean midrange and a bit more detail
The Paradigm Personas have the most 3d image, less bass then the Kefs, have a cleaner midrange, and tend to have the more prescence of all of these loudspeakers.
Which is better? Comes down to taste, most people will prefere the Kef Ref or the Paradigm over the less expensive speakers.
Some people prefer the Kefs other prefere the Persona B
Long story short loudspeakers are a personal choice. There is no better only what you prefer, and the matching electronics will also have a huge part to play.
Dave and Troy
Audio Doctor NJ Elac, Kef, Quad, Paradigm, Dali, ATC dealers