i have 4 ASC tube traps in my small room (2 larger ones in front corners, the 2 smaller ones in rear corners). They work very nice in my room. I found these at a local dealer who was going out of business. I paid $300 for all 4. There are many web sites that will show you how to make tube taps. here's a couple:
http://www.teresaudio.com/haven/traps/traps.html
http://ic.net/~jtgale/diy2.htm
http://www.geocities.com/jonrisch/a1.htm
http://www.teresaudio.com/haven/traps/traps.html
http://ic.net/~jtgale/diy2.htm
http://www.geocities.com/jonrisch/a1.htm