Platters: acrylic v. aluminum. What's the dif?

Only Harry can answer this question. As all know, VPI has moved on to aluminum. As with all things high end, it appears to be change for the sake of change. Better said, profit for the sake of profit.

I skipped Harry' all acrylic era. Felt the Aries I platter was never improved on.

So, let's see how the reviewer's will 'spin' the change.
Hi Jpxxx,
I have heard ~ both types of platters, with the same cart though not on an oracle, but some generalizations may apply.

It is pretty uncanny how at least in some set-ups a different 'sound picture' is painted, we are talking 'shades' or nuances.
It MUST have to do with the material's resonance behaviour, because an especially well damped alu-platter (constrained layer) example TransRotor's alu-platter, does yet 'sound' different (if actually at all) to a not so well damped one, example Thorens's 2010 alu-platter, and these vs. some 2" acrylic platter, all on mass, un-sprung tt's.

I had some more confirmation talking just a few days ago to a very experienced acoustics designer/engineer.
In fact he uses a simple test, by taking a music-box (German: "Spieluhr') and places it on the different materials he evaluates, and due to the little wind-up music-boxe's frequency range (the melody it plays), he can tell the colouration the material it is placed on imparts on the music signal. I thought that was rather interesting.

Back to platters. Acrylic = damped behaviour and imparting a minute plasticy signature (you need bat-ears to confirm it I guess). Alu-platter not using constrained layer damping of any kind = more brilliance, openness, but a minute metallic signature, some would call it 'faster' sounding.
Alu-platter constrained by vinyl as in Transrotor Z3 = close to Acrylic but slightly more 'open' and no easily perceivable signature to my ears at all.

TW Dacron TM with copper constrained layer = ???
I can only guess that it will sound just that bit less closed-in (nice word for dead plastic) then plain Dacron unconstrained.

If in doubt, get a music-box, listen and see what you shall find ---- and it might be 'zilch' to your ears after all.
Hi all,
small correction on that TW plastic name. It should have read "Delrin" TM.

I hope this will be correct now. Also see related information where one post describes acrylic as, quote: "...acrylic has a **sparkling top end**, transparent mids and a well textured but sometimes lean bass, Delrin has a bit muted top end, good midrange, and powerful bass."

I must say that "a sparkling top-end" etc. on an acrylic platter is just a bit out of my current experience. But as you can see, not so easy to pin down these rather delicate differences.