General question on Carbon fiber tonearms versus aluminum

Had Infinity Black Widow which is carbon fiber now i have TW ACUSTIC 10.5 which has better bass,midrange,depth,detail and dynamics.

Note that I and several other very experienced listeners have independently come to the same conclusion regarding carbon fiber in the vinyl reproduction path. It tends to kill the liveness of real music. Theories involving stiffness, hardness, compliance, damping, and blah blah blah are meaningless compared to actually listening to music. Theory is useful after the fact, to explain what you thought you heard.

I too had an Infinity Black Widow CF tonearm.  It was by far my least favorite of the tonearms I have had over the years.  Always seemed rather lifeless, dull, lacking dynamics.  Others have said the opposite about that same tonearm.  It all depends on so many variables, beginning with pairing the cartridge.  For me, it sat for years, barely every using it. I bought it when new, somewhere around 1981.  It initially sold for $250 and I got it for $125 (industry accommodation deal).  I sold it last year for $550.  I hope the new owner enjoys it greatly.

Theory before the fact CAN move the ball forward faster, vs. endless random wandering.....but of course, listening is essential 

I believe it would be a massive system engineering error to consider the tone arm in isolation....in a sense like letting the junior engineer paste a CF wing on an aluminum airplane.....

back to the music....

In particular, that has been true of the very few carbon fiber tonearms I have heard. They have tended to produce a sound that seems overdamped, lacking in dynamics.

@lewm I have both and the CF one is way less dynamic, less detailed, slower, and ultimately less musical than the aluminum ones. But it does have a taller and more expansive soundstage. I found the same thing with a Yamamoto CF headshell.