No problem, that's the earlier version of 避震 material, most of Ching here recommended to put under subwoofer, before this EVA thing become more popular here. If you search for "避震坑膠" here, you'll find a lot of interesting post
By the way, may be I put my A3X on my wooden desk, which have drawers, so, the desk is kind of echoing the bass, so, I never found A3X's bass is not enough. In the contrast, I found it perfectly at the right level instead, not too much, and not too thin.