Things like this are commonly available from your favourite store. These ones are from Audio Advisor:
http://www.audioadvisor.com/prodinfo.asp?number=AASONIC
I use these under my speakers on the hardwood floor, although a different brand. You can also use coins. However, with a coin it's easy to bump the speaker off the coin, when you vacuum for instance.
http://www.audioadvisor.com/prodinfo.asp?number=AASONIC
I use these under my speakers on the hardwood floor, although a different brand. You can also use coins. However, with a coin it's easy to bump the speaker off the coin, when you vacuum for instance.