Hi, P. The Herbie's mat is an excellent upgrade for the Pro-Ject metal platter. As Grinnell points out, the mat improves bass response, and I found that background noise was was quieted as well. Made for a more resolving mid-range and treble and seemed to increase dynamics as well. As David says, it's a relatively inexpensive upgrade that makes a noticeable improvement with that metal platter. I even use a Herbie's mat with the acrylic platter on my mmf-7 turntable.
The one good reason to replace the metal platter is if you want to use low output moving coil cartridges as they get pulled (magnetically) right down onto the metal platter. The acrylic platter isn't ferrous so doesn't affect LOMC cartridges, which contain strong magnets.
Tom
The one good reason to replace the metal platter is if you want to use low output moving coil cartridges as they get pulled (magnetically) right down onto the metal platter. The acrylic platter isn't ferrous so doesn't affect LOMC cartridges, which contain strong magnets.
Tom