Originally Posted by krosero
In 2008 they made the switch from Rebound Ace to Plexicushion. I am not sure but I have heard that Plexicushion is slower.
The AM's in '11 are lower than in '08, which is one piece of evidence that the Plexicushion itself was slowed down during the intervening years.
It's difficult to figure out exactly what court surface they are using and what speed it is. The companies that make Rebound Ace and Plexicusion each make several different products of various speeds that each carry the Rebound Ace or Plexicusion branding. From the ITF court pace classification page
Category 2, Medium-Slow:
Plexipave IW Acrylic
Category 3, Medium:
Rebound Ace GS 8mm
Rebound Ace Pro International Medium
Category 4, Medium-Fast:
Plexicushion Prestige AUS
Rebound Ace HSA Club
Rebound Ace Pro International
Rebound Ace Synpave
"Plexipave" refers to the acrylic surface itself while "Plexicushion" refers to the EPDM rubber sub-surface. Here are the three Plexipave top surfaces marketed by the company, from their website
Plexipave IW - ITF Category 1 - Pace: Slow
For those who desire a much slower surface, to compensate for lower humidity, high altitudes or simply to change the pace of the game, Plexipave has developed the I.W. mixture, first used at the Indian Wells, CA tournament facility.
Plexipave Standard - ITF Category 3 - Pace: Medium
Considered by many to be the best combination of consistency-of-play, pace and foothing. Plexipave Standard is the traditional and most widely used tennis court surface system. Standard Plexipave provides a consistent and reliable medium-pace playing surface.
Plexipave H.U. - ITF Category 4 - Pace: Medium-Fast
Harvard University has been the birthplace of many great innovations and playing traditions. Plexipave H.U. is no exception. It has also been adapted as the standard for the Australian Open Series.
So according to Plexipave, Plexipave H.U. has been adopted as the standard for the Australian Open series.
On the Plexicushion page
"PLEXICUSHION PRESTIGE - SURFACE OF THE AUSTRALIAN OPEN"
So according to Plexipave, the AO surface is a Plexipave H.U. acrylic topcoat over a Plexicushion Prestige subsurface. Both of these products are classified by ITF as "Medium-Fast" surfaces. The press, however, has consistently described the surface at the AO as "Medium". In short, there is no way of knowing if the courts are faster or slower from one year to the next without somebody in the know doing the telling.